651312510021 has 6 divisors (see below), whose sum is σ = 940784736710. Its totient is φ = 434208340008.

The previous prime is 651312509971. The next prime is 651312510077. The reversal of 651312510021 is 120015213156.

651312510021 is a `hidden beast` number, since 6 + 513 + 1 + 25 + 100 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 651311947521 + 562500 = 807039^2 + 750^2 .

It is not a de Polignac number, because 651312510021 - 2⁶ = 651312509957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (651312610021) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36184028326 + ... + 36184028343.

Almost surely, 2^651312510021 is an apocalyptic number.

It is an amenable number.

651312510021 is a deficient number, since it is larger than the sum of its proper divisors (289472226689).

651312510021 is a wasteful number, since it uses less digits than its factorization.

651312510021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72368056675 (or 72368056672 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

Adding to 651312510021 its reverse (120015213156), we get a palindrome (771327723177).

The spelling of 651312510021 in words is "six hundred fifty-one billion, three hundred twelve million, five hundred ten thousand, twenty-one".