20530591 has 4 divisors (see below), whose sum is σ = 20546352. Its totient is φ = 20514832.

The previous prime is 20530567. The next prime is 20530603. The reversal of 20530591 is 19503502.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20530591 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 (20530541) 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, 5731 + ... + 8596.

It is an arithmetic number, because the mean of its divisors is an integer number (5136588).

Almost surely, 2^20530591 is an apocalyptic number.

20530591 is the 2866-th heptagonal number.

20530591 is a deficient number, since it is larger than the sum of its proper divisors (15761).

20530591 is a wasteful number, since it uses less digits than its factorization.

20530591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15760.

The product of its (nonzero) digits is 1350, while the sum is 25.

The square root of 20530591 is about 4531.0695205437. The cubic root of 20530591 is about 273.8212510960.

The spelling of 20530591 in words is "twenty million, five hundred thirty thousand, five hundred ninety-one".