51297640 has 32 divisors (see below), whose sum is σ = 117602280. Its totient is φ = 20131072.

The previous prime is 51297637. The next prime is 51297671. The reversal of 51297640 is 4679215.

It can be written as a sum of positive squares in 4 ways, for example, as 39967684 + 11329956 = 6322^2 + 3366^2 .

It is a junction number, because it is equal to n+sod(n) for n = 51297596 and 51297605.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9979 + ... + 14218.

Almost surely, 2^51297640 is an apocalyptic number.

It is an amenable number.

51297640 is an abundant number, since it is smaller than the sum of its proper divisors (66304640).

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

51297640 is a wasteful number, since it uses less digits than its factorization.

51297640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24261 (or 24257 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 51297640 is about 7162.2370806892. The cubic root of 51297640 is about 371.5630009321.

It can be divided in two parts, 5129 and 7640, that added together give a square (12769 = 113²).

The spelling of 51297640 in words is "fifty-one million, two hundred ninety-seven thousand, six hundred forty".