21953265 has 16 divisors (see below), whose sum is σ = 36974400. Its totient is φ = 11092032.

The previous prime is 21953233. The next prime is 21953279. The reversal of 21953265 is 56235912.

It is not a de Polignac number, because 21953265 - 2⁵ = 21953233 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38230 + ... + 38799.

It is an arithmetic number, because the mean of its divisors is an integer number (2310900).

Almost surely, 2^21953265 is an apocalyptic number.

It is an amenable number.

21953265 is a deficient number, since it is larger than the sum of its proper divisors (15021135).

21953265 is a wasteful number, since it uses less digits than its factorization.

21953265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77056.

The product of its digits is 16200, while the sum is 33.

The square root of 21953265 is about 4685.4311434488. The cubic root of 21953265 is about 280.0053782981.

It can be divided in two parts, 2195 and 3265, that added together give a triangular number (5460 = T₁₀₄).

The spelling of 21953265 in words is "twenty-one million, nine hundred fifty-three thousand, two hundred sixty-five".