21573880 has 16 divisors (see below), whose sum is σ = 48541320. Its totient is φ = 8629536.

The previous prime is 21573863. The next prime is 21573887. The reversal of 21573880 is 8837512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21573887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 269634 + ... + 269713.

Almost surely, 2^21573880 is an apocalyptic number.

21573880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21573880 is an abundant number, since it is smaller than the sum of its proper divisors (26967440).

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

21573880 is a wasteful number, since it uses less digits than its factorization.

21573880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 539358 (or 539354 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 21573880 is about 4644.7691008273. The cubic root of 21573880 is about 278.3830270513.

The spelling of 21573880 in words is "twenty-one million, five hundred seventy-three thousand, eight hundred eighty".