21393500 has 24 divisors (see below), whose sum is σ = 46724496. Its totient is φ = 8557200.

The previous prime is 21393481. The next prime is 21393521. The reversal of 21393500 is 539312.

It is a happy number.

It is a congruent 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, 20894 + ... + 21893.

It is an arithmetic number, because the mean of its divisors is an integer number (1946854).

Almost surely, 2^21393500 is an apocalyptic number.

21393500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21393500 is an abundant number, since it is smaller than the sum of its proper divisors (25330996).

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

21393500 is a wasteful number, since it uses less digits than its factorization.

21393500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42806 (or 42794 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 23.

The square root of 21393500 is about 4625.3108003679. The cubic root of 21393500 is about 277.6049977369.

The spelling of 21393500 in words is "twenty-one million, three hundred ninety-three thousand, five hundred".