21656251635143 has 2 divisors, whose sum is σ = 21656251635144. Its totient is φ = 21656251635142.

The previous prime is 21656251634999. The next prime is 21656251635163. The reversal of 21656251635143 is 34153615265612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21656251635143 - 2¹⁶ = 21656251569607 is a prime.

It is a super-2 number, since 2×21656251635143² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21656251635091 and 21656251635100.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21656251635163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10828125817571 + 10828125817572.

It is an arithmetic number, because the mean of its divisors is an integer number (10828125817572).

Almost surely, 2^{21656251635143} is an apocalyptic number.

21656251635143 is a deficient number, since it is larger than the sum of its proper divisors (1).

21656251635143 is an equidigital number, since it uses as much as digits as its factorization.

21656251635143 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888000, while the sum is 50.

The spelling of 21656251635143 in words is "twenty-one trillion, six hundred fifty-six billion, two hundred fifty-one million, six hundred thirty-five thousand, one hundred forty-three".