20408139 has 16 divisors (see below), whose sum is σ = 30506400. Its totient is φ = 13483008.

The previous prime is 20408117. The next prime is 20408189. The reversal of 20408139 is 93180402.

It is not a de Polignac number, because 20408139 - 2⁸ = 20407883 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (20408189) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 294 + ... + 6395.

It is an arithmetic number, because the mean of its divisors is an integer number (1906650).

Almost surely, 2^20408139 is an apocalyptic number.

20408139 is a deficient number, since it is larger than the sum of its proper divisors (10098261).

20408139 is a wasteful number, since it uses less digits than its factorization.

20408139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6811 (or 6805 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 20408139 is about 4517.5368288482. The cubic root of 20408139 is about 273.2757749448.

The spelling of 20408139 in words is "twenty million, four hundred eight thousand, one hundred thirty-nine".