21885013 has 2 divisors, whose sum is σ = 21885014. Its totient is φ = 21885012.

The previous prime is 21884987. The next prime is 21885023. The reversal of 21885013 is 31058812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14691889 + 7193124 = 3833^2 + 2682^2 .

It is a cyclic number.

It is not a de Polignac number, because 21885013 - 2⁵ = 21884981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21885023) 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, 10942506 + 10942507.

It is an arithmetic number, because the mean of its divisors is an integer number (10942507).

Almost surely, 2^21885013 is an apocalyptic number.

It is an amenable number.

21885013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21885013 is an equidigital number, since it uses as much as digits as its factorization.

21885013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 21885013 is about 4678.1420457271. The cubic root of 21885013 is about 279.7149011345.

The spelling of 21885013 in words is "twenty-one million, eight hundred eighty-five thousand, thirteen".