51023440 has 80 divisors (see below), whose sum is σ = 129741696. Its totient is φ = 18547200.

The previous prime is 51023429. The next prime is 51023447. The reversal of 51023440 is 4432015.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51023447) 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, 73495 + ... + 74185.

Almost surely, 2^51023440 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51023440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (64870848).

51023440 is an abundant number, since it is smaller than the sum of its proper divisors (78718256).

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

51023440 is a wasteful number, since it uses less digits than its factorization.

51023440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 788 (or 782 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 51023440 is about 7143.0693682758. The cubic root of 51023440 is about 370.8997823384.

Adding to 51023440 its reverse (4432015), we get a palindrome (55455455).

The spelling of 51023440 in words is "fifty-one million, twenty-three thousand, four hundred forty".