129431785 has 24 divisors (see below), whose sum is σ = 186916680. Its totient is φ = 85688064.

The previous prime is 129431767. The next prime is 129431821. The reversal of 129431785 is 587134921.

It can be written as a sum of positive squares in 4 ways, for example, as 4618201 + 124813584 = 2149^2 + 11172^2 .

It is a de Polignac number, because none of the positive numbers 2^k-129431785 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2004 + ... + 16213.

It is an arithmetic number, because the mean of its divisors is an integer number (7788195).

Almost surely, 2^129431785 is an apocalyptic number.

It is an amenable number.

129431785 is a deficient number, since it is larger than the sum of its proper divisors (57484895).

129431785 is a wasteful number, since it uses less digits than its factorization.

129431785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18265 (or 18258 counting only the distinct ones).

The product of its digits is 60480, while the sum is 40.

The square root of 129431785 is about 11376.8090869101. The cubic root of 129431785 is about 505.8405568140.

The spelling of 129431785 in words is "one hundred twenty-nine million, four hundred thirty-one thousand, seven hundred eighty-five".