21159629 has 2 divisors, whose sum is σ = 21159630. Its totient is φ = 21159628.

The previous prime is 21159623. The next prime is 21159631. The reversal of 21159629 is 92695112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15984004 + 5175625 = 3998^2 + 2275^2 .

It is a cyclic number.

It is not a de Polignac number, because 21159629 - 2⁴ = 21159613 is a prime.

Together with 21159631, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21159623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10579814 + 10579815.

It is an arithmetic number, because the mean of its divisors is an integer number (10579815).

Almost surely, 2^21159629 is an apocalyptic number.

It is an amenable number.

21159629 is a deficient number, since it is larger than the sum of its proper divisors (1).

21159629 is an equidigital number, since it uses as much as digits as its factorization.

21159629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9720, while the sum is 35.

The square root of 21159629 is about 4599.9596737363. The cubic root of 21159629 is about 276.5897082768.

The spelling of 21159629 in words is "twenty-one million, one hundred fifty-nine thousand, six hundred twenty-nine".