21953285 has 4 divisors (see below), whose sum is σ = 26343948. Its totient is φ = 17562624.

The previous prime is 21953279. The next prime is 21953299. The reversal of 21953285 is 58235912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5094049 + 16859236 = 2257^2 + 4106^2 .

It is a cyclic number.

It is not a de Polignac number, because 21953285 - 2⁶ = 21953221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2195324 + ... + 2195333.

It is an arithmetic number, because the mean of its divisors is an integer number (6585987).

Almost surely, 2^21953285 is an apocalyptic number.

It is an amenable number.

21953285 is a deficient number, since it is larger than the sum of its proper divisors (4390663).

21953285 is an equidigital number, since it uses as much as digits as its factorization.

21953285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4390662.

The product of its digits is 21600, while the sum is 35.

The square root of 21953285 is about 4685.4332777236. The cubic root of 21953285 is about 280.0054633288.

The spelling of 21953285 in words is "twenty-one million, nine hundred fifty-three thousand, two hundred eighty-five".