20139769 has 4 divisors (see below), whose sum is σ = 21688996. Its totient is φ = 18590544.

The previous prime is 20139737. The next prime is 20139773. The reversal of 20139769 is 96793102.

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 11799225 + 8340544 = 3435^2 + 2888^2 .

It is a cyclic number.

It is not a de Polignac number, because 20139769 - 2⁵ = 20139737 is a prime.

It is a super-2 number, since 2×20139769² = 811220590746722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20139269) 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, 774594 + ... + 774619.

It is an arithmetic number, because the mean of its divisors is an integer number (5422249).

Almost surely, 2^20139769 is an apocalyptic number.

It is an amenable number.

20139769 is a deficient number, since it is larger than the sum of its proper divisors (1549227).

20139769 is a wasteful number, since it uses less digits than its factorization.

20139769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1549226.

The product of its (nonzero) digits is 20412, while the sum is 37.

The square root of 20139769 is about 4487.7353977257. The cubic root of 20139769 is about 272.0726134348.

The spelling of 20139769 in words is "twenty million, one hundred thirty-nine thousand, seven hundred sixty-nine".