21656251635163 has 2 divisors, whose sum is σ = 21656251635164. Its totient is φ = 21656251635162.

The previous prime is 21656251635143. The next prime is 21656251635181. The reversal of 21656251635163 is 36153615265612.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21656251635163 is a prime.

It is a super-2 number, since 2×21656251635163² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21656251635163.

It is not a weakly prime, because it can be changed into another prime (21656251635143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10828125817581 + 10828125817582.

It is an arithmetic number, because the mean of its divisors is an integer number (10828125817582).

Almost surely, 2^{21656251635163} is an apocalyptic number.

21656251635163 is a deficient number, since it is larger than the sum of its proper divisors (1).

21656251635163 is an equidigital number, since it uses as much as digits as its factorization.

21656251635163 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5832000, while the sum is 52.

The spelling of 21656251635163 in words is "twenty-one trillion, six hundred fifty-six billion, two hundred fifty-one million, six hundred thirty-five thousand, one hundred sixty-three".