21953268 has 30 divisors (see below), whose sum is σ = 57391026. Its totient is φ = 7317648.

The previous prime is 21953233. The next prime is 21953279. The reversal of 21953268 is 86235912.

It can be written as a sum of positive squares in only one way, i.e., 21734244 + 219024 = 4662^2 + 468^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 33555 + ... + 34202.

Almost surely, 2^21953268 is an apocalyptic number.

It is an amenable number.

21953268 is an abundant number, since it is smaller than the sum of its proper divisors (35437758).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21953268 is a wasteful number, since it uses less digits than its factorization.

21953268 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67773 (or 67762 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 21953268 is about 4685.4314635901. The cubic root of 21953268 is about 280.0053910527.

It can be divided in two parts, 21 and 953268, that multiplied together give a triangular number (20018628 = T₆₃₂₇).

The spelling of 21953268 in words is "twenty-one million, nine hundred fifty-three thousand, two hundred sixty-eight".