21629137 has 2 divisors, whose sum is σ = 21629138. Its totient is φ = 21629136.

The previous prime is 21629123. The next prime is 21629143. The reversal of 21629137 is 73192612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13242321 + 8386816 = 3639^2 + 2896^2 .

21629137 is a truncatable prime.

It is a cyclic number.

It is not a de Polignac number, because 21629137 - 2⁷ = 21629009 is a prime.

It is equal to p_1367239 and since 21629137 and 1367239 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21629099 and 21629108.

It is not a weakly prime, because it can be changed into another prime (21629437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10814568 + 10814569.

It is an arithmetic number, because the mean of its divisors is an integer number (10814569).

Almost surely, 2^21629137 is an apocalyptic number.

It is an amenable number.

21629137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21629137 is an equidigital number, since it uses as much as digits as its factorization.

21629137 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4536, while the sum is 31.

The square root of 21629137 is about 4650.7136011584. The cubic root of 21629137 is about 278.6204978024.

The spelling of 21629137 in words is "twenty-one million, six hundred twenty-nine thousand, one hundred thirty-seven".