1551316440 has 128 divisors (see below), whose sum is σ = 4717440000. Its totient is φ = 408089088.

The previous prime is 1551316433. The next prime is 1551316447. The reversal of 1551316440 is 446131551.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1551316433) and next prime (1551316447).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1551316398 and 1551316407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1551316447) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3987766 + ... + 3988154.

It is an arithmetic number, because the mean of its divisors is an integer number (36855000).

Almost surely, 2^1551316440 is an apocalyptic number.

1551316440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1551316440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2358720000).

1551316440 is an abundant number, since it is smaller than the sum of its proper divisors (3166123560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1551316440 is a wasteful number, since it uses less digits than its factorization.

1551316440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 769 (or 765 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 1551316440 is about 39386.7546263969. The cubic root of 1551316440 is about 1157.6220708538.

Adding to 1551316440 its reverse (446131551), we get a palindrome (1997447991).

The spelling of 1551316440 in words is "one billion, five hundred fifty-one million, three hundred sixteen thousand, four hundred forty".