21285400 has 24 divisors (see below), whose sum is σ = 49489020. Its totient is φ = 8514080.

The previous prime is 21285367. The next prime is 21285409. The reversal of 21285400 is 458212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21285409) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 53014 + ... + 53413.

Almost surely, 2^21285400 is an apocalyptic number.

21285400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21285400 is an abundant number, since it is smaller than the sum of its proper divisors (28203620).

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

21285400 is a wasteful number, since it uses less digits than its factorization.

21285400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106443 (or 106434 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 22.

The square root of 21285400 is about 4613.6102999712. The cubic root of 21285400 is about 277.1366344908.

The spelling of 21285400 in words is "twenty-one million, two hundred eighty-five thousand, four hundred".