21629123 has 2 divisors, whose sum is σ = 21629124. Its totient is φ = 21629122.

The previous prime is 21629119. The next prime is 21629137. The reversal of 21629123 is 32192612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21629123 - 2² = 21629119 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21629092 and 21629101.

It is not a weakly prime, because it can be changed into another prime (21629143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10814561 + 10814562.

It is an arithmetic number, because the mean of its divisors is an integer number (10814562).

Almost surely, 2^21629123 is an apocalyptic number.

21629123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21629123 is an equidigital number, since it uses as much as digits as its factorization.

21629123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 26.

The square root of 21629123 is about 4650.7120960128. The cubic root of 21629123 is about 278.6204376877.

The spelling of 21629123 in words is "twenty-one million, six hundred twenty-nine thousand, one hundred twenty-three".