21625633 has 2 divisors, whose sum is σ = 21625634. Its totient is φ = 21625632.

The previous prime is 21625621. The next prime is 21625661. The reversal of 21625633 is 33652612.

It is an a-pointer prime, because the next prime (21625661) can be obtained adding 21625633 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21095649 + 529984 = 4593^2 + 728^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21625633 is a prime.

It is not a weakly prime, because it can be changed into another prime (21625673) 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, 10812816 + 10812817.

It is an arithmetic number, because the mean of its divisors is an integer number (10812817).

Almost surely, 2^21625633 is an apocalyptic number.

It is an amenable number.

21625633 is a deficient number, since it is larger than the sum of its proper divisors (1).

21625633 is an equidigital number, since it uses as much as digits as its factorization.

21625633 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6480, while the sum is 28.

The square root of 21625633 is about 4650.3368695182. The cubic root of 21625633 is about 278.6054511403.

The spelling of 21625633 in words is "twenty-one million, six hundred twenty-five thousand, six hundred thirty-three".