21102110957 has 2 divisors, whose sum is σ = 21102110958. Its totient is φ = 21102110956.

The previous prime is 21102110941. The next prime is 21102110969. The reversal of 21102110957 is 75901120112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20042348041 + 1059762916 = 141571^2 + 32554^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102110957 - 2⁴ = 21102110941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102110257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551055478 + 10551055479.

It is an arithmetic number, because the mean of its divisors is an integer number (10551055479).

Almost surely, 2^21102110957 is an apocalyptic number.

It is an amenable number.

21102110957 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102110957 is an equidigital number, since it uses as much as digits as its factorization.

21102110957 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1260, while the sum is 29.

The spelling of 21102110957 in words is "twenty-one billion, one hundred two million, one hundred ten thousand, nine hundred fifty-seven".