21710266157 has 2 divisors, whose sum is σ = 21710266158. Its totient is φ = 21710266156.

The previous prime is 21710266117. The next prime is 21710266159. The reversal of 21710266157 is 75166201712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19503239716 + 2207026441 = 139654^2 + 46979^2 .

It is a cyclic number.

It is not a de Polignac number, because 21710266157 - 2⁸ = 21710265901 is a prime.

Together with 21710266159, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21710266157.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21710266159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10855133078 + 10855133079.

It is an arithmetic number, because the mean of its divisors is an integer number (10855133079).

Almost surely, 2^21710266157 is an apocalyptic number.

It is an amenable number.

21710266157 is a deficient number, since it is larger than the sum of its proper divisors (1).

21710266157 is an equidigital number, since it uses as much as digits as its factorization.

21710266157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 35280, while the sum is 38.

Adding to 21710266157 its reverse (75166201712), we get a palindrome (96876467869).

The spelling of 21710266157 in words is "twenty-one billion, seven hundred ten million, two hundred sixty-six thousand, one hundred fifty-seven".