51392640 has 256 divisors, whose sum is σ = 185068800. Its totient is φ = 12042240.

The previous prime is 51392629. The next prime is 51392659. The reversal of 51392640 is 4629315.

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 = 51392598 and 51392607.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 723805 + ... + 723875.

It is an arithmetic number, because the mean of its divisors is an integer number (722925).

Almost surely, 2^51392640 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 51392640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92534400).

51392640 is an abundant number, since it is smaller than the sum of its proper divisors (133676160).

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

51392640 is a wasteful number, since it uses less digits than its factorization.

51392640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 123 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 51392640 is about 7168.8660191135. The cubic root of 51392640 is about 371.7922299134.

The spelling of 51392640 in words is "fifty-one million, three hundred ninety-two thousand, six hundred forty".