21952815 has 8 divisors (see below), whose sum is σ = 35124528. Its totient is φ = 11708160.

The previous prime is 21952811. The next prime is 21952823. The reversal of 21952815 is 51825912.

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

It is not a de Polignac number, because 21952815 - 2² = 21952811 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21952811) 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, 731746 + ... + 731775.

It is an arithmetic number, because the mean of its divisors is an integer number (4390566).

Almost surely, 2^21952815 is an apocalyptic number.

21952815 is a deficient number, since it is larger than the sum of its proper divisors (13171713).

21952815 is a wasteful number, since it uses less digits than its factorization.

21952815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1463529.

The product of its digits is 7200, while the sum is 33.

The square root of 21952815 is about 4685.3831220083. The cubic root of 21952815 is about 280.0034650932.

The spelling of 21952815 in words is "twenty-one million, nine hundred fifty-two thousand, eight hundred fifteen".