21889240 has 32 divisors (see below), whose sum is σ = 50063760. Its totient is φ = 8611200.

The previous prime is 21889223. The next prime is 21889247. The reversal of 21889240 is 4298812.

21889240 = 1201² + 1202² + ... + 1215².

It is a junction number, because it is equal to n+sod(n) for n = 21889196 and 21889205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21889247) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2046 + ... + 6925.

Almost surely, 2^21889240 is an apocalyptic number.

21889240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21889240 is an abundant number, since it is smaller than the sum of its proper divisors (28174520).

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

21889240 is a wasteful number, since it uses less digits than its factorization.

21889240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9043 (or 9039 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 21889240 is about 4678.5938058353. The cubic root of 21889240 is about 279.7329085683.

The spelling of 21889240 in words is "twenty-one million, eight hundred eighty-nine thousand, two hundred forty".