21943090 has 32 divisors (see below), whose sum is σ = 45042480. Its totient is φ = 7624704.

The previous prime is 21943087. The next prime is 21943091. The reversal of 21943090 is 9034912.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 5239521 + 16703569 = 2289^2 + 4087^2 .

It is not an unprimeable number, because it can be changed into a prime (21943091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2755 + ... + 7174.

Almost surely, 2^21943090 is an apocalyptic number.

21943090 is an abundant number, since it is smaller than the sum of its proper divisors (23099390).

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

21943090 is a wasteful number, since it uses less digits than its factorization.

21943090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9966.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 21943090 is about 4684.3452050420. The cubic root of 21943090 is about 279.9621122204.

The spelling of 21943090 in words is "twenty-one million, nine hundred forty-three thousand, ninety".