21890633 has 4 divisors (see below), whose sum is σ = 22037700. Its totient is φ = 21743568.

The previous prime is 21890629. The next prime is 21890647. The reversal of 21890633 is 33609812.

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 5914624 + 15976009 = 2432^2 + 3997^2 .

It is a cyclic number.

It is not a de Polignac number, because 21890633 - 2² = 21890629 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21890633.

It is not an unprimeable number, because it can be changed into a prime (21890623) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73310 + ... + 73607.

It is an arithmetic number, because the mean of its divisors is an integer number (5509425).

Almost surely, 2^21890633 is an apocalyptic number.

It is an amenable number.

21890633 is a deficient number, since it is larger than the sum of its proper divisors (147067).

21890633 is a wasteful number, since it uses less digits than its factorization.

21890633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147066.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 21890633 is about 4678.7426729838. The cubic root of 21890633 is about 279.7388423769.

The spelling of 21890633 in words is "twenty-one million, eight hundred ninety thousand, six hundred thirty-three".