20623657 has 4 divisors (see below), whose sum is σ = 20786176. Its totient is φ = 20461140.

The previous prime is 20623643. The next prime is 20623693. The reversal of 20623657 is 75632602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20623657 - 2¹¹ = 20621609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20623957) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81069 + ... + 81322.

It is an arithmetic number, because the mean of its divisors is an integer number (5196544).

Almost surely, 2^20623657 is an apocalyptic number.

It is an amenable number.

20623657 is a deficient number, since it is larger than the sum of its proper divisors (162519).

20623657 is a wasteful number, since it uses less digits than its factorization.

20623657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162518.

The product of its (nonzero) digits is 15120, while the sum is 31.

The square root of 20623657 is about 4541.3276693055. The cubic root of 20623657 is about 274.2343750923.

The spelling of 20623657 in words is "twenty million, six hundred twenty-three thousand, six hundred fifty-seven".