21670505651 has 8 divisors (see below), whose sum is σ = 23185011600. Its totient is φ = 20193395040.

The previous prime is 21670505609. The next prime is 21670505653. The reversal of 21670505651 is 15650507612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21670505651 - 2³⁴ = 4490636467 is a prime.

It is a super-2 number, since 2×21670505651² (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 (21670505653) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9347636 + ... + 9349953.

It is an arithmetic number, because the mean of its divisors is an integer number (2898126450).

Almost surely, 2^21670505651 is an apocalyptic number.

21670505651 is a deficient number, since it is larger than the sum of its proper divisors (1514505949).

21670505651 is a wasteful number, since it uses less digits than its factorization.

21670505651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18697669.

The product of its (nonzero) digits is 63000, while the sum is 38.

The spelling of 21670505651 in words is "twenty-one billion, six hundred seventy million, five hundred five thousand, six hundred fifty-one".