21323129 has 2 divisors, whose sum is σ = 21323130. Its totient is φ = 21323128.

The previous prime is 21323089. The next prime is 21323153. The reversal of 21323129 is 92132312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18905104 + 2418025 = 4348^2 + 1555^2 .

It is a cyclic number.

It is not a de Polignac number, because 21323129 - 2¹² = 21319033 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21323189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10661564 + 10661565.

It is an arithmetic number, because the mean of its divisors is an integer number (10661565).

Almost surely, 2^21323129 is an apocalyptic number.

It is an amenable number.

21323129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21323129 is an equidigital number, since it uses as much as digits as its factorization.

21323129 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 23.

The square root of 21323129 is about 4617.6973699020. The cubic root of 21323129 is about 277.3002821280.

The spelling of 21323129 in words is "twenty-one million, three hundred twenty-three thousand, one hundred twenty-nine".