20139969 has 4 divisors (see below), whose sum is σ = 26853296. Its totient is φ = 13426644.

The previous prime is 20139937. The next prime is 20139971. The reversal of 20139969 is 96993102.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20139969 - 2⁵ = 20139937 is a prime.

It is a super-2 number, since 2×20139969² = 811236702641922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20139919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3356659 + ... + 3356664.

It is an arithmetic number, because the mean of its divisors is an integer number (6713324).

Almost surely, 2^20139969 is an apocalyptic number.

It is an amenable number.

20139969 is a deficient number, since it is larger than the sum of its proper divisors (6713327).

20139969 is an equidigital number, since it uses as much as digits as its factorization.

20139969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6713326.

The product of its (nonzero) digits is 26244, while the sum is 39.

The square root of 20139969 is about 4487.7576806240. The cubic root of 20139969 is about 272.0735140466.

The spelling of 20139969 in words is "twenty million, one hundred thirty-nine thousand, nine hundred sixty-nine".