21244290 has 32 divisors (see below), whose sum is σ = 52367040. Its totient is φ = 5511744.

The previous prime is 21244277. The next prime is 21244291. The reversal of 21244290 is 9244212.

It is a self number, because there is not a number n which added to its sum of digits gives 21244290.

It is not an unprimeable number, because it can be changed into a prime (21244291) 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, 8460 + ... + 10679.

It is an arithmetic number, because the mean of its divisors is an integer number (1636470).

Almost surely, 2^21244290 is an apocalyptic number.

21244290 is an abundant number, since it is smaller than the sum of its proper divisors (31122750).

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

21244290 is a wasteful number, since it uses less digits than its factorization.

21244290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19186.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 21244290 is about 4609.1528505789. The cubic root of 21244290 is about 276.9581016360.

The spelling of 21244290 in words is "twenty-one million, two hundred forty-four thousand, two hundred ninety".