51651940 has 24 divisors (see below), whose sum is σ = 108699192. Its totient is φ = 20616960.

The previous prime is 51651907. The next prime is 51651949. The reversal of 51651940 is 4915615.

It can be written as a sum of positive squares in 4 ways, for example, as 7986276 + 43665664 = 2826^2 + 6608^2 .

It is not an unprimeable number, because it can be changed into a prime (51651949) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7942 + ... + 12898.

It is an arithmetic number, because the mean of its divisors is an integer number (4529133).

Almost surely, 2^51651940 is an apocalyptic number.

It is an amenable number.

51651940 is an abundant number, since it is smaller than the sum of its proper divisors (57047252).

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

51651940 is a wasteful number, since it uses less digits than its factorization.

51651940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5487 (or 5485 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 51651940 is about 7186.9284120548. The cubic root of 51651940 is about 372.4164700173.

The spelling of 51651940 in words is "fifty-one million, six hundred fifty-one thousand, nine hundred forty".