20657745 has 24 divisors (see below), whose sum is σ = 35919936. Its totient is φ = 10982688.

The previous prime is 20657743. The next prime is 20657779. The reversal of 20657745 is 54775602.

It is not a de Polignac number, because 20657745 - 2¹ = 20657743 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20657743) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 20524 + ... + 21506.

It is an arithmetic number, because the mean of its divisors is an integer number (1496664).

Almost surely, 2^20657745 is an apocalyptic number.

It is an amenable number.

20657745 is a deficient number, since it is larger than the sum of its proper divisors (15262191).

20657745 is a wasteful number, since it uses less digits than its factorization.

20657745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1461 (or 1458 counting only the distinct ones).

The product of its (nonzero) digits is 58800, while the sum is 36.

The square root of 20657745 is about 4545.0792072306. The cubic root of 20657745 is about 274.3853821896.

The spelling of 20657745 in words is "twenty million, six hundred fifty-seven thousand, seven hundred forty-five".