20139785 has 4 divisors (see below), whose sum is σ = 24167748. Its totient is φ = 16111824.

The previous prime is 20139773. The next prime is 20139793. The reversal of 20139785 is 58793102.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10916416 + 9223369 = 3304^2 + 3037^2 .

It is a cyclic number.

It is not a de Polignac number, because 20139785 - 2⁸ = 20139529 is a prime.

It is a super-2 number, since 2×20139785² = 811221879692450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2013974 + ... + 2013983.

It is an arithmetic number, because the mean of its divisors is an integer number (6041937).

Almost surely, 2^20139785 is an apocalyptic number.

It is an amenable number.

20139785 is a deficient number, since it is larger than the sum of its proper divisors (4027963).

20139785 is an equidigital number, since it uses as much as digits as its factorization.

20139785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4027962.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 20139785 is about 4487.7371803616. The cubic root of 20139785 is about 272.0726854840.

The spelling of 20139785 in words is "twenty million, one hundred thirty-nine thousand, seven hundred eighty-five".