21285270 has 24 divisors (see below), whose sum is σ = 55341936. Its totient is φ = 5676048.

The previous prime is 21285269. The next prime is 21285283. The reversal of 21285270 is 7258212.

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 11 ways as a sum of consecutive naturals, for example, 118162 + ... + 118341.

It is an arithmetic number, because the mean of its divisors is an integer number (2305914).

Almost surely, 2^21285270 is an apocalyptic number.

21285270 is an abundant number, since it is smaller than the sum of its proper divisors (34056666).

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

21285270 is a wasteful number, since it uses less digits than its factorization.

21285270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236516 (or 236513 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 21285270 is about 4613.5962112001. The cubic root of 21285270 is about 277.1360702881.

The spelling of 21285270 in words is "twenty-one million, two hundred eighty-five thousand, two hundred seventy".