129191931 has 12 divisors (see below), whose sum is σ = 203575320. Its totient is φ = 78298080.

The previous prime is 129191929. The next prime is 129191941. The reversal of 129191931 is 139191921.

It is not a de Polignac number, because 129191931 - 2¹ = 129191929 is a prime.

It is a super-2 number, since 2×129191931² = 33381110071017522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (129191941) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 652386 + ... + 652583.

It is an arithmetic number, because the mean of its divisors is an integer number (16964610).

Almost surely, 2^129191931 is an apocalyptic number.

129191931 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

129191931 is a deficient number, since it is larger than the sum of its proper divisors (74383389).

129191931 is a wasteful number, since it uses less digits than its factorization.

129191931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1304986 (or 1304983 counting only the distinct ones).

The product of its digits is 4374, while the sum is 36.

The square root of 129191931 is about 11366.2628422890. The cubic root of 129191931 is about 505.5279007338.

The spelling of 129191931 in words is "one hundred twenty-nine million, one hundred ninety-one thousand, nine hundred thirty-one".