21456970 has 16 divisors (see below), whose sum is σ = 38792520. Its totient is φ = 8545024.

The previous prime is 21456959. The next prime is 21456971. The reversal of 21456970 is 7965412.

It can be written as a sum of positive squares in 4 ways, for example, as 10093329 + 11363641 = 3177^2 + 3371^2 .

It is a zygodrome in base 9.

It is not an unprimeable number, because it can be changed into a prime (21456971) by changing a digit.

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, 2275 + ... + 6934.

Almost surely, 2^21456970 is an apocalyptic number.

21456970 is a deficient number, since it is larger than the sum of its proper divisors (17335550).

21456970 is a wasteful number, since it uses less digits than its factorization.

21456970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9449.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 21456970 is about 4632.1668795500. The cubic root of 21456970 is about 277.8792585067.

The spelling of 21456970 in words is "twenty-one million, four hundred fifty-six thousand, nine hundred seventy".