51921668 has 12 divisors (see below), whose sum is σ = 90997452. Its totient is φ = 25922400.

The previous prime is 51921659. The next prime is 51921671. The reversal of 51921668 is 86612915.

It can be written as a sum of positive squares in 2 ways, for example, as 30558784 + 21362884 = 5528^2 + 4622^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6455 + ... + 12062.

It is an arithmetic number, because the mean of its divisors is an integer number (7583121).

Almost surely, 2^51921668 is an apocalyptic number.

It is an amenable number.

51921668 is a deficient number, since it is larger than the sum of its proper divisors (39075784).

51921668 is a wasteful number, since it uses less digits than its factorization.

51921668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19222 (or 19220 counting only the distinct ones).

The product of its digits is 25920, while the sum is 38.

The square root of 51921668 is about 7205.6691569902. The cubic root of 51921668 is about 373.0636015813.

The spelling of 51921668 in words is "fifty-one million, nine hundred twenty-one thousand, six hundred sixty-eight".