21989528 has 16 divisors (see below), whose sum is σ = 44978760. Its totient is φ = 9995200.

The previous prime is 21989521. The next prime is 21989537. The reversal of 21989528 is 82598912.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21989521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 124853 + ... + 125028.

Almost surely, 2^21989528 is an apocalyptic number.

It is an amenable number.

21989528 is an abundant number, since it is smaller than the sum of its proper divisors (22989232).

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

21989528 is a wasteful number, since it uses less digits than its factorization.

21989528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249898 (or 249894 counting only the distinct ones).

The product of its digits is 103680, while the sum is 44.

The square root of 21989528 is about 4689.2993079990. The cubic root of 21989528 is about 280.1594669855.

The spelling of 21989528 in words is "twenty-one million, nine hundred eighty-nine thousand, five hundred twenty-eight".