21625993 has 2 divisors, whose sum is σ = 21625994. Its totient is φ = 21625992.

The previous prime is 21625987. The next prime is 21626029. The reversal of 21625993 is 39952612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21455424 + 170569 = 4632^2 + 413^2 .

It is a cyclic number.

It is not a de Polignac number, because 21625993 - 2²¹ = 19528841 is a prime.

It is not a weakly prime, because it can be changed into another prime (21625913) 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, 10812996 + 10812997.

It is an arithmetic number, because the mean of its divisors is an integer number (10812997).

Almost surely, 2^21625993 is an apocalyptic number.

It is an amenable number.

21625993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21625993 is an equidigital number, since it uses as much as digits as its factorization.

21625993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 29160, while the sum is 37.

The square root of 21625993 is about 4650.3755762304. The cubic root of 21625993 is about 278.6069971051.

The spelling of 21625993 in words is "twenty-one million, six hundred twenty-five thousand, nine hundred ninety-three".