21093820 has 24 divisors (see below), whose sum is σ = 48324528. Its totient is φ = 7670400.

The previous prime is 21093799. The next prime is 21093833. The reversal of 21093820 is 2839012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47721 + ... + 48160.

It is an arithmetic number, because the mean of its divisors is an integer number (2013522).

Almost surely, 2^21093820 is an apocalyptic number.

21093820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21093820 is an abundant number, since it is smaller than the sum of its proper divisors (27230708).

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

21093820 is a wasteful number, since it uses less digits than its factorization.

21093820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95901 (or 95899 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 21093820 is about 4592.8008883469. The cubic root of 21093820 is about 276.3026680359.

It can be divided in two parts, 2109 and 3820, that added together give a square (5929 = 77²).

The spelling of 21093820 in words is "twenty-one million, ninety-three thousand, eight hundred twenty".