21880240 has 20 divisors (see below), whose sum is σ = 50871744. Its totient is φ = 8752064.

The previous prime is 21880231. The next prime is 21880247. The reversal of 21880240 is 4208812.

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (21880247) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 136672 + ... + 136831.

Almost surely, 2^21880240 is an apocalyptic number.

21880240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21880240 is an abundant number, since it is smaller than the sum of its proper divisors (28991504).

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

21880240 is a wasteful number, since it uses less digits than its factorization.

21880240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273516 (or 273510 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 21880240 is about 4677.6318794877. The cubic root of 21880240 is about 279.6945648996.

The spelling of 21880240 in words is "twenty-one million, eight hundred eighty thousand, two hundred forty".