21696629 has 2 divisors, whose sum is σ = 21696630. Its totient is φ = 21696628.

The previous prime is 21696617. The next prime is 21696707. The reversal of 21696629 is 92669612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21141604 + 555025 = 4598^2 + 745^2 .

It is a cyclic number.

It is not a de Polignac number, because 21696629 - 2²⁴ = 4919413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21696529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10848314 + 10848315.

It is an arithmetic number, because the mean of its divisors is an integer number (10848315).

Almost surely, 2^21696629 is an apocalyptic number.

It is an amenable number.

21696629 is a deficient number, since it is larger than the sum of its proper divisors (1).

21696629 is an equidigital number, since it uses as much as digits as its factorization.

21696629 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69984, while the sum is 41.

The square root of 21696629 is about 4657.9640402219. The cubic root of 21696629 is about 278.9100012471.

The spelling of 21696629 in words is "twenty-one million, six hundred ninety-six thousand, six hundred twenty-nine".