139931805 has 32 divisors (see below), whose sum is σ = 242613504. Its totient is φ = 68461056.

The previous prime is 139931797. The next prime is 139931821. The reversal of 139931805 is 508139931.

139931805 = 167² + 168² + ... + 751².

It is not a de Polignac number, because 139931805 - 2³ = 139931797 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 30417 + ... + 34713.

It is an arithmetic number, because the mean of its divisors is an integer number (7581672).

Almost surely, 2^139931805 is an apocalyptic number.

139931805 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

139931805 is a deficient number, since it is larger than the sum of its proper divisors (102681699).

139931805 is a wasteful number, since it uses less digits than its factorization.

139931805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4485.

The product of its (nonzero) digits is 29160, while the sum is 39.

The square root of 139931805 is about 11829.2774504616. The cubic root of 139931805 is about 519.1650864599.

The spelling of 139931805 in words is "one hundred thirty-nine million, nine hundred thirty-one thousand, eight hundred five".