21889021 has 24 divisors (see below), whose sum is σ = 28183232. Its totient is φ = 16632000.

The previous prime is 21889019. The next prime is 21889061. The reversal of 21889021 is 12098812.

It is a happy number.

It is not a de Polignac number, because 21889021 - 2¹ = 21889019 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21889001) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 36121 + ... + 36721.

Almost surely, 2^21889021 is an apocalyptic number.

It is an amenable number.

21889021 is a deficient number, since it is larger than the sum of its proper divisors (6294211).

21889021 is a wasteful number, since it uses less digits than its factorization.

21889021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 673 (or 662 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 21889021 is about 4678.5704013085. The cubic root of 21889021 is about 279.7319756638.

The spelling of 21889021 in words is "twenty-one million, eight hundred eighty-nine thousand, twenty-one".