21617653139 has 2 divisors, whose sum is σ = 21617653140. Its totient is φ = 21617653138.

The previous prime is 21617653093. The next prime is 21617653217. The reversal of 21617653139 is 93135671612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21617653139 - 2⁸ = 21617652883 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21617653139.

It is not a weakly prime, because it can be changed into another prime (21617653039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10808826569 + 10808826570.

It is an arithmetic number, because the mean of its divisors is an integer number (10808826570).

Almost surely, 2^21617653139 is an apocalyptic number.

21617653139 is a deficient number, since it is larger than the sum of its proper divisors (1).

21617653139 is an equidigital number, since it uses as much as digits as its factorization.

21617653139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 204120, while the sum is 44.

The spelling of 21617653139 in words is "twenty-one billion, six hundred seventeen million, six hundred fifty-three thousand, one hundred thirty-nine".