20660531 has 4 divisors (see below), whose sum is σ = 20670864. Its totient is φ = 20650200.

The previous prime is 20660527. The next prime is 20660567. The reversal of 20660531 is 13506602.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20660531 - 2² = 20660527 is a prime.

It is a super-2 number, since 2×20660531² = 853715082403922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20660497 and 20660506.

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, 1100 + ... + 6521.

It is an arithmetic number, because the mean of its divisors is an integer number (5167716).

Almost surely, 2^20660531 is an apocalyptic number.

20660531 is a deficient number, since it is larger than the sum of its proper divisors (10333).

20660531 is an equidigital number, since it uses as much as digits as its factorization.

20660531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10332.

The product of its (nonzero) digits is 1080, while the sum is 23.

The square root of 20660531 is about 4545.3856822056. The cubic root of 20660531 is about 274.3977165999.

The spelling of 20660531 in words is "twenty million, six hundred sixty thousand, five hundred thirty-one".