21415129 has 2 divisors, whose sum is σ = 21415130. Its totient is φ = 21415128.

The previous prime is 21415099. The next prime is 21415133. The reversal of 21415129 is 92151412.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16216729 + 5198400 = 4027^2 + 2280^2 .

It is a cyclic number.

It is not a de Polignac number, because 21415129 - 2²³ = 13026521 is a prime.

It is not a weakly prime, because it can be changed into another prime (21415159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10707564 + 10707565.

It is an arithmetic number, because the mean of its divisors is an integer number (10707565).

Almost surely, 2^21415129 is an apocalyptic number.

It is an amenable number.

21415129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21415129 is an equidigital number, since it uses as much as digits as its factorization.

21415129 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 25.

The square root of 21415129 is about 4627.6483228525. The cubic root of 21415129 is about 277.6985198528.

The spelling of 21415129 in words is "twenty-one million, four hundred fifteen thousand, one hundred twenty-nine".