129438761 has 4 divisors (see below), whose sum is σ = 130695552. Its totient is φ = 128181972.

The previous prime is 129438739. The next prime is 129438769. The reversal of 129438761 is 167834921.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-129438761 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (129438769) 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, 628241 + ... + 628446.

It is an arithmetic number, because the mean of its divisors is an integer number (32673888).

Almost surely, 2^129438761 is an apocalyptic number.

It is an amenable number.

129438761 is a deficient number, since it is larger than the sum of its proper divisors (1256791).

129438761 is a wasteful number, since it uses less digits than its factorization.

129438761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1256790.

The product of its digits is 72576, while the sum is 41.

The square root of 129438761 is about 11377.1156713817. The cubic root of 129438761 is about 505.8496444332.

The spelling of 129438761 in words is "one hundred twenty-nine million, four hundred thirty-eight thousand, seven hundred sixty-one".