51329640 has 128 divisors (see below), whose sum is σ = 165888000. Its totient is φ = 12665088.

The previous prime is 51329639. The next prime is 51329651. The reversal of 51329640 is 4692315.

51329640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 = 51329598 and 51329607.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 106921 + ... + 107399.

It is an arithmetic number, because the mean of its divisors is an integer number (1296000).

Almost surely, 2^51329640 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 51329640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82944000).

51329640 is an abundant number, since it is smaller than the sum of its proper divisors (114558360).

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

51329640 is a wasteful number, since it uses less digits than its factorization.

51329640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 559 (or 555 counting only the distinct ones).

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

The square root of 51329640 is about 7164.4706713057. The cubic root of 51329640 is about 371.6402464903.

The spelling of 51329640 in words is "fifty-one million, three hundred twenty-nine thousand, six hundred forty".