21893860 has 12 divisors (see below), whose sum is σ = 45977148. Its totient is φ = 8757536.

The previous prime is 21893831. The next prime is 21893887. The reversal of 21893860 is 6839812.

It can be written as a sum of positive squares in 2 ways, for example, as 5116644 + 16777216 = 2262^2 + 4096^2 .

It is a super-3 number, since 3×21893860³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 3 ways as a sum of consecutive naturals, for example, 547327 + ... + 547366.

It is an arithmetic number, because the mean of its divisors is an integer number (3831429).

Almost surely, 2^21893860 is an apocalyptic number.

21893860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21893860 is an abundant number, since it is smaller than the sum of its proper divisors (24083288).

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

21893860 is a wasteful number, since it uses less digits than its factorization.

21893860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1094702 (or 1094700 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 21893860 is about 4679.0875178821. The cubic root of 21893860 is about 279.7525875693.

The spelling of 21893860 in words is "twenty-one million, eight hundred ninety-three thousand, eight hundred sixty".