651687621 has 16 divisors (see below), whose sum is σ = 936774720. Its totient is φ = 400602240.

The previous prime is 651687599. The next prime is 651687667. The reversal of 651687621 is 126786156.

It is a de Polignac number, because none of the positive numbers 2^k-651687621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (651687671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29265 + ... + 46473.

It is an arithmetic number, because the mean of its divisors is an integer number (58548420).

Almost surely, 2^651687621 is an apocalyptic number.

It is an amenable number.

651687621 is a deficient number, since it is larger than the sum of its proper divisors (285087099).

651687621 is a wasteful number, since it uses less digits than its factorization.

651687621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18196.

The product of its digits is 120960, while the sum is 42.

The square root of 651687621 is about 25528.1730838695. The cubic root of 651687621 is about 866.9881412101.

The spelling of 651687621 in words is "six hundred fifty-one million, six hundred eighty-seven thousand, six hundred twenty-one".