21210622681 has 4 divisors (see below), whose sum is σ = 21211239952. Its totient is φ = 21210005412.

The previous prime is 21210622651. The next prime is 21210622687. The reversal of 21210622681 is 18622601212.

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 21210622681 - 2²⁷ = 21076404953 is a prime.

It is a super-2 number, since 2×21210622681² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21210622687) 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, 253851 + ... + 326896.

It is an arithmetic number, because the mean of its divisors is an integer number (5302809988).

Almost surely, 2^21210622681 is an apocalyptic number.

It is an amenable number.

21210622681 is a deficient number, since it is larger than the sum of its proper divisors (617271).

21210622681 is an equidigital number, since it uses as much as digits as its factorization.

21210622681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 617270.

The product of its (nonzero) digits is 4608, while the sum is 31.

The spelling of 21210622681 in words is "twenty-one billion, two hundred ten million, six hundred twenty-two thousand, six hundred eighty-one".