21696129 has 48 divisors (see below), whose sum is σ = 39312000. Its totient is φ = 11225088.

The previous prime is 21696127. The next prime is 21696137. The reversal of 21696129 is 92169612.

It is not a de Polignac number, because 21696129 - 2¹ = 21696127 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21696093 and 21696102.

It is not an unprimeable number, because it can be changed into a prime (21696121) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 48097 + ... + 48545.

It is an arithmetic number, because the mean of its divisors is an integer number (819000).

Almost surely, 2^21696129 is an apocalyptic number.

It is an amenable number.

21696129 is a deficient number, since it is larger than the sum of its proper divisors (17615871).

21696129 is a wasteful number, since it uses less digits than its factorization.

21696129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 534 (or 531 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 21696129 is about 4657.9103683948. The cubic root of 21696129 is about 278.9078587319.

The spelling of 21696129 in words is "twenty-one million, six hundred ninety-six thousand, one hundred twenty-nine".