21252913 has 8 divisors (see below), whose sum is σ = 23342400. Its totient is φ = 19189680.

The previous prime is 21252899. The next prime is 21252919. The reversal of 21252913 is 31925212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21252913 - 2⁹ = 21252401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21252919) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4845 + ... + 8122.

It is an arithmetic number, because the mean of its divisors is an integer number (2917800).

Almost surely, 2^21252913 is an apocalyptic number.

It is an amenable number.

21252913 is a deficient number, since it is larger than the sum of its proper divisors (2089487).

21252913 is a wasteful number, since it uses less digits than its factorization.

21252913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13127.

The product of its digits is 1080, while the sum is 25.

The square root of 21252913 is about 4610.0881770309. The cubic root of 21252913 is about 276.9955687492.

The spelling of 21252913 in words is "twenty-one million, two hundred fifty-two thousand, nine hundred thirteen".