20660591 has 4 divisors (see below), whose sum is σ = 23612112. Its totient is φ = 17709072.

The previous prime is 20660587. The next prime is 20660603. The reversal of 20660591 is 19506602.

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

It is a cyclic number.

It is not a de Polignac number, because 20660591 - 2² = 20660587 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 (20660501) 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, 1475750 + ... + 1475763.

It is an arithmetic number, because the mean of its divisors is an integer number (5903028).

Almost surely, 2^20660591 is an apocalyptic number.

20660591 is a deficient number, since it is larger than the sum of its proper divisors (2951521).

20660591 is an equidigital number, since it uses as much as digits as its factorization.

20660591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2951520.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 20660591 is about 4545.3922823008. The cubic root of 20660591 is about 274.3979822247.

The spelling of 20660591 in words is "twenty million, six hundred sixty thousand, five hundred ninety-one".