129551531 has 2 divisors, whose sum is σ = 129551532. Its totient is φ = 129551530.

The previous prime is 129551501. The next prime is 129551537. The reversal of 129551531 is 135155921.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 129551531 - 2¹⁰ = 129550507 is a prime.

It is a super-2 number, since 2×129551531² = 33567198368887922, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (129551537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64775765 + 64775766.

It is an arithmetic number, because the mean of its divisors is an integer number (64775766).

Almost surely, 2^129551531 is an apocalyptic number.

129551531 is a deficient number, since it is larger than the sum of its proper divisors (1).

129551531 is an equidigital number, since it uses as much as digits as its factorization.

129551531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6750, while the sum is 32.

The square root of 129551531 is about 11382.0705937013. The cubic root of 129551531 is about 505.9965043737.

The spelling of 129551531 in words is "one hundred twenty-nine million, five hundred fifty-one thousand, five hundred thirty-one".