20406539 has 2 divisors, whose sum is σ = 20406540. Its totient is φ = 20406538.

The previous prime is 20406523. The next prime is 20406559. The reversal of 20406539 is 93560402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20406539 - 2⁴ = 20406523 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20406559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10203269 + 10203270.

It is an arithmetic number, because the mean of its divisors is an integer number (10203270).

Almost surely, 2^20406539 is an apocalyptic number.

20406539 is a deficient number, since it is larger than the sum of its proper divisors (1).

20406539 is an equidigital number, since it uses as much as digits as its factorization.

20406539 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 20406539 is about 4517.3597377229. The cubic root of 20406539 is about 273.2686331428.

The spelling of 20406539 in words is "twenty million, four hundred six thousand, five hundred thirty-nine".