21318290 has 32 divisors (see below), whose sum is σ = 45045504. Its totient is φ = 7110720.

The previous prime is 21318287. The next prime is 21318299. The reversal of 21318290 is 9281312.

It is not an unprimeable number, because it can be changed into a prime (21318299) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1526 + ... + 6705.

It is an arithmetic number, because the mean of its divisors is an integer number (1407672).

Almost surely, 2^21318290 is an apocalyptic number.

21318290 is an abundant number, since it is smaller than the sum of its proper divisors (23727214).

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

21318290 is a wasteful number, since it uses less digits than its factorization.

21318290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8282.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 21318290 is about 4617.1733777280. The cubic root of 21318290 is about 277.2793040063.

The spelling of 21318290 in words is "twenty-one million, three hundred eighteen thousand, two hundred ninety".