21889620 has 36 divisors (see below), whose sum is σ = 66399060. Its totient is φ = 5837184.

The previous prime is 21889601. The next prime is 21889643. The reversal of 21889620 is 2698812.

21889620 is a `hidden beast` number, since 21 + 8 + 8 + 9 + 620 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2547216 + 19342404 = 1596^2 + 4398^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-4 number, since 4×21889620⁴ (a number of 30 digits) contains 4444 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 60625 + ... + 60984.

Almost surely, 2^21889620 is an apocalyptic number.

21889620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21889620 is an abundant number, since it is smaller than the sum of its proper divisors (44509440).

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

21889620 is a wasteful number, since it uses less digits than its factorization.

21889620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121624 (or 121619 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 21889620 is about 4678.6344161518. The cubic root of 21889620 is about 279.7345272920.

The spelling of 21889620 in words is "twenty-one million, eight hundred eighty-nine thousand, six hundred twenty".