20539531 has 2 divisors, whose sum is σ = 20539532. Its totient is φ = 20539530.

The previous prime is 20539523. The next prime is 20539537. The reversal of 20539531 is 13593502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20539531 - 2³ = 20539523 is a prime.

It is a super-2 number, since 2×20539531² = 843744667399922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20539531.

It is not a weakly prime, because it can be changed into another prime (20539537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10269765 + 10269766.

It is an arithmetic number, because the mean of its divisors is an integer number (10269766).

Almost surely, 2^20539531 is an apocalyptic number.

20539531 is a deficient number, since it is larger than the sum of its proper divisors (1).

20539531 is an equidigital number, since it uses as much as digits as its factorization.

20539531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4050, while the sum is 28.

The square root of 20539531 is about 4532.0559352241. The cubic root of 20539531 is about 273.8609902792.

The spelling of 20539531 in words is "twenty million, five hundred thirty-nine thousand, five hundred thirty-one".