21089040 has 80 divisors (see below), whose sum is σ = 74721408. Its totient is φ = 4819968.

The previous prime is 21089011. The next prime is 21089051. The reversal of 21089040 is 4098012.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21089040.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4597 + ... + 7956.

Almost surely, 2^21089040 is an apocalyptic number.

21089040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21089040 is an abundant number, since it is smaller than the sum of its proper divisors (53632368).

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

21089040 is a wasteful number, since it uses less digits than its factorization.

21089040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12576 (or 12570 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 21089040 is about 4592.2804792390. The cubic root of 21089040 is about 276.2817957847.

The spelling of 21089040 in words is "twenty-one million, eighty-nine thousand, forty".