21292913 has 2 divisors, whose sum is σ = 21292914. Its totient is φ = 21292912.

The previous prime is 21292897. The next prime is 21292919. The reversal of 21292913 is 31929212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10975969 + 10316944 = 3313^2 + 3212^2 .

It is a cyclic number.

It is not a de Polignac number, because 21292913 - 2⁴ = 21292897 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21292919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10646456 + 10646457.

It is an arithmetic number, because the mean of its divisors is an integer number (10646457).

Almost surely, 2^21292913 is an apocalyptic number.

It is an amenable number.

21292913 is a deficient number, since it is larger than the sum of its proper divisors (1).

21292913 is an equidigital number, since it uses as much as digits as its factorization.

21292913 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944, while the sum is 29.

The square root of 21292913 is about 4614.4244494845. The cubic root of 21292913 is about 277.1692371607.

The spelling of 21292913 in words is "twenty-one million, two hundred ninety-two thousand, nine hundred thirteen".