20656945 has 8 divisors (see below), whose sum is σ = 24897960. Its totient is φ = 16452480.

The previous prime is 20656927. The next prime is 20656963. The reversal of 20656945 is 54965602.

It is an interprime number because it is at equal distance from previous prime (20656927) and next prime (20656963).

It can be written as a sum of positive squares in 4 ways, for example, as 1682209 + 18974736 = 1297^2 + 4356^2 .

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

It is a de Polignac number, because none of the positive numbers 2^k-20656945 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7876 + ... + 10165.

It is an arithmetic number, because the mean of its divisors is an integer number (3112245).

Almost surely, 2^20656945 is an apocalyptic number.

It is an amenable number.

20656945 is a deficient number, since it is larger than the sum of its proper divisors (4241015).

20656945 is a wasteful number, since it uses less digits than its factorization.

20656945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18275.

The product of its (nonzero) digits is 64800, while the sum is 37.

The square root of 20656945 is about 4544.9911991114. The cubic root of 20656945 is about 274.3818401582.

The spelling of 20656945 in words is "twenty million, six hundred fifty-six thousand, nine hundred forty-five".