139129891 has 4 divisors (see below), whose sum is σ = 143617984. Its totient is φ = 134641800.

The previous prime is 139129877. The next prime is 139129901. The reversal of 139129891 is 198921931.

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

It is a cyclic number.

It is not a de Polignac number, because 139129891 - 2⁹ = 139129379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139129801) 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, 2244000 + ... + 2244061.

It is an arithmetic number, because the mean of its divisors is an integer number (35904496).

Almost surely, 2^139129891 is an apocalyptic number.

139129891 is a deficient number, since it is larger than the sum of its proper divisors (4488093).

139129891 is an equidigital number, since it uses as much as digits as its factorization.

139129891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4488092.

The product of its digits is 34992, while the sum is 43.

The square root of 139129891 is about 11795.3334416624. Note that the first 3 decimals coincide. The cubic root of 139129891 is about 518.1714510746.

The spelling of 139129891 in words is "one hundred thirty-nine million, one hundred twenty-nine thousand, eight hundred ninety-one".