20976709 has 4 divisors (see below), whose sum is σ = 22590316. Its totient is φ = 19363104.

The previous prime is 20976701. The next prime is 20976719. The reversal of 20976709 is 90767902.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2184484 + 18792225 = 1478^2 + 4335^2 .

It is a cyclic number.

It is not a de Polignac number, because 20976709 - 2³ = 20976701 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20976701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 806784 + ... + 806809.

It is an arithmetic number, because the mean of its divisors is an integer number (5647579).

Almost surely, 2^20976709 is an apocalyptic number.

It is an amenable number.

20976709 is a deficient number, since it is larger than the sum of its proper divisors (1613607).

20976709 is a wasteful number, since it uses less digits than its factorization.

20976709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1613606.

The product of its (nonzero) digits is 47628, while the sum is 40.

The square root of 20976709 is about 4580.0337335002. The cubic root of 20976709 is about 275.7903829179.

The spelling of 20976709 in words is "twenty million, nine hundred seventy-six thousand, seven hundred nine".