851621000521 has 4 divisors (see below), whose sum is σ = 871426140112. Its totient is φ = 831815860932.

The previous prime is 851621000501. The next prime is 851621000551. The reversal of 851621000521 is 125000126158.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 851621000521 - 2¹⁵ = 851620967753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (851621000501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9902569731 + ... + 9902569816.

It is an arithmetic number, because the mean of its divisors is an integer number (217856535028).

Almost surely, 2^851621000521 is an apocalyptic number.

It is an amenable number.

851621000521 is a deficient number, since it is larger than the sum of its proper divisors (19805139591).

851621000521 is a wasteful number, since it uses less digits than its factorization.

851621000521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19805139590.

The product of its (nonzero) digits is 4800, while the sum is 31.

Adding to 851621000521 its reverse (125000126158), we get a palindrome (976621126679).

The spelling of 851621000521 in words is "eight hundred fifty-one billion, six hundred twenty-one million, five hundred twenty-one", and thus it is an aban number.