129287691 has 32 divisors (see below), whose sum is σ = 207072320. Its totient is φ = 79252992.

The previous prime is 129287681. The next prime is 129287693. The reversal of 129287691 is 196782921.

It is not a de Polignac number, because 129287691 - 2¹¹ = 129285643 is a prime.

It is a super-2 number, since 2×129287691² = 33430614088222962, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (129287693) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 117741 + ... + 118833.

It is an arithmetic number, because the mean of its divisors is an integer number (6471010).

Almost surely, 2^129287691 is an apocalyptic number.

129287691 is a deficient number, since it is larger than the sum of its proper divisors (77784629).

129287691 is a wasteful number, since it uses less digits than its factorization.

129287691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1452 (or 1446 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The square root of 129287691 is about 11370.4745283563. The cubic root of 129287691 is about 505.6527728153.

The spelling of 129287691 in words is "one hundred twenty-nine million, two hundred eighty-seven thousand, six hundred ninety-one".