21365970 has 16 divisors (see below), whose sum is σ = 51278400. Its totient is φ = 5697584.

The previous prime is 21365947. The next prime is 21365987. The reversal of 21365970 is 7956312.

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, 356070 + ... + 356129.

It is an arithmetic number, because the mean of its divisors is an integer number (3204900).

Almost surely, 2^21365970 is an apocalyptic number.

21365970 is an abundant number, since it is smaller than the sum of its proper divisors (29912430).

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

21365970 is a wasteful number, since it uses less digits than its factorization.

21365970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 712209.

The product of its (nonzero) digits is 11340, while the sum is 33.

The square root of 21365970 is about 4622.3338261099. Note that the first 3 decimals coincide. The cubic root of 21365970 is about 277.4858689339.

The spelling of 21365970 in words is "twenty-one million, three hundred sixty-five thousand, nine hundred seventy".