20436139 has 4 divisors (see below), whose sum is σ = 20741224. Its totient is φ = 20131056.

The previous prime is 20436133. The next prime is 20436151. The reversal of 20436139 is 93163402.

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 20436139 - 2⁵ = 20436107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20436133) 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, 152442 + ... + 152575.

It is an arithmetic number, because the mean of its divisors is an integer number (5185306).

Almost surely, 2^20436139 is an apocalyptic number.

20436139 is a deficient number, since it is larger than the sum of its proper divisors (305085).

20436139 is an equidigital number, since it uses as much as digits as its factorization.

20436139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305084.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 20436139 is about 4520.6348005562. The cubic root of 20436139 is about 273.4006961012.

The spelling of 20436139 in words is "twenty million, four hundred thirty-six thousand, one hundred thirty-nine".