129075021 has 12 divisors (see below), whose sum is σ = 187218460. Its totient is φ = 85691520.

The previous prime is 129075013. The next prime is 129075029. The reversal of 129075021 is 120570921.

It is an interprime number because it is at equal distance from previous prime (129075013) and next prime (129075029).

It can be written as a sum of positive squares in 2 ways, for example, as 45077796 + 83997225 = 6714^2 + 9165^2 .

It is not a de Polignac number, because 129075021 - 2³ = 129075013 is a prime.

It is a super-2 number, since 2×129075021² = 33320722092300882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129075029) 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, 27586 + ... + 31923.

Almost surely, 2^129075021 is an apocalyptic number.

It is an amenable number.

129075021 is a deficient number, since it is larger than the sum of its proper divisors (58143439).

129075021 is a wasteful number, since it uses less digits than its factorization.

129075021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59756 (or 59753 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 129075021 is about 11361.1188269466. The cubic root of 129075021 is about 505.3753651409.

The spelling of 129075021 in words is "one hundred twenty-nine million, seventy-five thousand, twenty-one".