21317829651 has 12 divisors (see below), whose sum is σ = 30798206712. Its totient is φ = 14209215936.

The previous prime is 21317829647. The next prime is 21317829667. The reversal of 21317829651 is 15692871312.

It is not a de Polignac number, because 21317829651 - 2² = 21317829647 is a prime.

It is a super-2 number, since 2×21317829651² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21317829597 and 21317829606.

It is not an unprimeable number, because it can be changed into a prime (21317829641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 171366 + ... + 268331.

It is an arithmetic number, because the mean of its divisors is an integer number (2566517226).

Almost surely, 2^21317829651 is an apocalyptic number.

21317829651 is a deficient number, since it is larger than the sum of its proper divisors (9480377061).

21317829651 is a wasteful number, since it uses less digits than its factorization.

21317829651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 445090 (or 445087 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The spelling of 21317829651 in words is "twenty-one billion, three hundred seventeen million, eight hundred twenty-nine thousand, six hundred fifty-one".