51721608 has 16 divisors (see below), whose sum is σ = 129304080. Its totient is φ = 17240528.

The previous prime is 51721603. The next prime is 51721613. The reversal of 51721608 is 80612715.

It is an interprime number because it is at equal distance from previous prime (51721603) and next prime (51721613).

It is not an unprimeable number, because it can be changed into a prime (51721601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1077510 + ... + 1077557.

It is an arithmetic number, because the mean of its divisors is an integer number (8081505).

Almost surely, 2^51721608 is an apocalyptic number.

It is an amenable number.

51721608 is an abundant number, since it is smaller than the sum of its proper divisors (77582472).

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

51721608 is a wasteful number, since it uses less digits than its factorization.

51721608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2155076 (or 2155072 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 51721608 is about 7191.7736338125. The cubic root of 51721608 is about 372.5838329100.

The spelling of 51721608 in words is "fifty-one million, seven hundred twenty-one thousand, six hundred eight".