21151687933 has 2 divisors, whose sum is σ = 21151687934. Its totient is φ = 21151687932.

The previous prime is 21151687897. The next prime is 21151687981. The reversal of 21151687933 is 33978615112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16434470809 + 4717217124 = 128197^2 + 68682^2 .

It is a cyclic number.

It is not a de Polignac number, because 21151687933 - 2²⁹ = 20614817021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21151681933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10575843966 + 10575843967.

It is an arithmetic number, because the mean of its divisors is an integer number (10575843967).

Almost surely, 2^21151687933 is an apocalyptic number.

It is an amenable number.

21151687933 is a deficient number, since it is larger than the sum of its proper divisors (1).

21151687933 is an equidigital number, since it uses as much as digits as its factorization.

21151687933 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 272160, while the sum is 46.

The spelling of 21151687933 in words is "twenty-one billion, one hundred fifty-one million, six hundred eighty-seven thousand, nine hundred thirty-three".