1551440 has 80 divisors (see below), whose sum is σ = 4124736. Its totient is φ = 537600.

The previous prime is 1551383. The next prime is 1551449. The reversal of 1551440 is 441551.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1551449) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36059 + ... + 36101.

2^1551440 is an apocalyptic number.

1551440 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 1551440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2062368).

1551440 is an abundant number, since it is smaller than the sum of its proper divisors (2573296).

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

1551440 is a wasteful number, since it uses less digits than its factorization.

1551440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108 (or 102 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 1551440 is about 1245.5681434590. The cubic root of 1551440 is about 115.7652804318.

Adding to 1551440 its reverse (441551), we get a palindrome (1992991).

It can be divided in two parts, 1551 and 440, that added together give a palindrome (1991).

The spelling of 1551440 in words is "one million, five hundred fifty-one thousand, four hundred forty".