20570661 has 6 divisors (see below), whose sum is σ = 29713190. Its totient is φ = 13713768.

The previous prime is 20570653. The next prime is 20570677. The reversal of 20570661 is 16607502.

It can be written as a sum of positive squares in only one way, i.e., 10929636 + 9641025 = 3306^2 + 3105^2 .

It is not a de Polignac number, because 20570661 - 2³ = 20570653 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 (20570681) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1142806 + ... + 1142823.

Almost surely, 2^20570661 is an apocalyptic number.

It is an amenable number.

20570661 is a deficient number, since it is larger than the sum of its proper divisors (9142529).

20570661 is a wasteful number, since it uses less digits than its factorization.

20570661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2285635 (or 2285632 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 20570661 is about 4535.4890585250. The cubic root of 20570661 is about 273.9992762870. Note that the first 3 decimals are identical.

The spelling of 20570661 in words is "twenty million, five hundred seventy thousand, six hundred sixty-one".