51621636 has 24 divisors (see below), whose sum is σ = 131400864. Its totient is φ = 15642880.

The previous prime is 51621617. The next prime is 51621659. The reversal of 51621636 is 63612615.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

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, 195405 + ... + 195668.

It is an arithmetic number, because the mean of its divisors is an integer number (5475036).

Almost surely, 2^51621636 is an apocalyptic number.

It is an amenable number.

51621636 is an abundant number, since it is smaller than the sum of its proper divisors (79779228).

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

51621636 is a wasteful number, since it uses less digits than its factorization.

51621636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 391091 (or 391089 counting only the distinct ones).

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

The square root of 51621636 is about 7184.8198307264. The cubic root of 51621636 is about 372.3436239859.

The spelling of 51621636 in words is "fifty-one million, six hundred twenty-one thousand, six hundred thirty-six".