21952690 has 16 divisors (see below), whose sum is σ = 39683160. Its totient is φ = 8743680.

The previous prime is 21952673. The next prime is 21952691. The reversal of 21952690 is 9625912.

It can be written as a sum of positive squares in 4 ways, for example, as 15896169 + 6056521 = 3987^2 + 2461^2 .

It is a super-2 number, since 2×21952690² = 963841196472200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21952691) 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, 2145 + ... + 6964.

Almost surely, 2^21952690 is an apocalyptic number.

21952690 is a deficient number, since it is larger than the sum of its proper divisors (17730470).

21952690 is a wasteful number, since it uses less digits than its factorization.

21952690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9357.

The product of its (nonzero) digits is 9720, while the sum is 34.

The square root of 21952690 is about 4685.3697826319. The cubic root of 21952690 is about 280.0029336427.

The spelling of 21952690 in words is "twenty-one million, nine hundred fifty-two thousand, six hundred ninety".