21292290 has 48 divisors (see below), whose sum is σ = 55598400. Its totient is φ = 5653536.

The previous prime is 21292289. The next prime is 21292291. The reversal of 21292290 is 9229212.

It is an interprime number because it is at equal distance from previous prime (21292289) and next prime (21292291).

It is a super-2 number, since 2×21292290² = 906723226888200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21292291) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31981 + ... + 32639.

It is an arithmetic number, because the mean of its divisors is an integer number (1158300).

Almost surely, 2^21292290 is an apocalyptic number.

21292290 is an abundant number, since it is smaller than the sum of its proper divisors (34306110).

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

21292290 is a wasteful number, since it uses less digits than its factorization.

21292290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1031 (or 1028 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 21292290 is about 4614.3569432804. The cubic root of 21292290 is about 277.1665339433.

The spelling of 21292290 in words is "twenty-one million, two hundred ninety-two thousand, two hundred ninety".