21151970 has 16 divisors (see below), whose sum is σ = 43512768. Its totient is φ = 7252080.

The previous prime is 21151937. The next prime is 21151979. The reversal of 21151970 is 7915112.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21151979) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 151016 + ... + 151155.

It is an arithmetic number, because the mean of its divisors is an integer number (2719548).

Almost surely, 2^21151970 is an apocalyptic number.

21151970 is an abundant number, since it is smaller than the sum of its proper divisors (22360798).

21151970 is a wasteful number, since it uses less digits than its factorization.

21151970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302185.

The product of its (nonzero) digits is 630, while the sum is 26.

The square root of 21151970 is about 4599.1270910902. The cubic root of 21151970 is about 276.5563325149.

The spelling of 21151970 in words is "twenty-one million, one hundred fifty-one thousand, nine hundred seventy".