21070609 has 8 divisors (see below), whose sum is σ = 24111360. Its totient is φ = 18037536.

The previous prime is 21070603. The next prime is 21070613. The reversal of 21070609 is 90607012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21070609 - 2⁷ = 21070481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21070603) 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, 6357 + ... + 9085.

It is an arithmetic number, because the mean of its divisors is an integer number (3013920).

Almost surely, 2^21070609 is an apocalyptic number.

It is an amenable number.

21070609 is a deficient number, since it is larger than the sum of its proper divisors (3040751).

21070609 is a wasteful number, since it uses less digits than its factorization.

21070609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3839.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 21070609 is about 4590.2733034102. The cubic root of 21070609 is about 276.2012858145.

The spelling of 21070609 in words is "twenty-one million, seventy thousand, six hundred nine".