21538760 has 32 divisors (see below), whose sum is σ = 48608640. Its totient is φ = 8589504.

The previous prime is 21538757. The next prime is 21538789. The reversal of 21538760 is 6783512.

It is a happy number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 17939 + ... + 19101.

It is an arithmetic number, because the mean of its divisors is an integer number (1519020).

Almost surely, 2^21538760 is an apocalyptic number.

21538760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21538760 is an abundant number, since it is smaller than the sum of its proper divisors (27069880).

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

21538760 is a wasteful number, since it uses less digits than its factorization.

21538760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1637 (or 1633 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 21538760 is about 4640.9869639981. The cubic root of 21538760 is about 278.2318856105.

The spelling of 21538760 in words is "twenty-one million, five hundred thirty-eight thousand, seven hundred sixty".