21093870 has 32 divisors (see below), whose sum is σ = 57858048. Its totient is φ = 4821408.

The previous prime is 21093833. The next prime is 21093899. The reversal of 21093870 is 7839012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

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, 50014 + ... + 50433.

It is an arithmetic number, because the mean of its divisors is an integer number (1808064).

Almost surely, 2^21093870 is an apocalyptic number.

21093870 is an abundant number, since it is smaller than the sum of its proper divisors (36764178).

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

21093870 is a wasteful number, since it uses less digits than its factorization.

21093870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100464.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 21093870 is about 4592.8063316452. The cubic root of 21093870 is about 276.3028863482.

The spelling of 21093870 in words is "twenty-one million, ninety-three thousand, eight hundred seventy".