129455021 has 4 divisors (see below), whose sum is σ = 129602844. Its totient is φ = 129307200.

The previous prime is 129454987. The next prime is 129455023. The reversal of 129455021 is 120554921.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 36120100 + 93334921 = 6010^2 + 9661^2 .

It is a cyclic number.

It is not a de Polignac number, because 129455021 - 2⁶ = 129454957 is a prime.

It is a super-2 number, since 2×129455021² = 33517204924220882, 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 (129455023) 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, 72590 + ... + 74351.

It is an arithmetic number, because the mean of its divisors is an integer number (32400711).

Almost surely, 2^129455021 is an apocalyptic number.

It is an amenable number.

129455021 is a deficient number, since it is larger than the sum of its proper divisors (147823).

129455021 is an equidigital number, since it uses as much as digits as its factorization.

129455021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147822.

The product of its (nonzero) digits is 3600, while the sum is 29.

The square root of 129455021 is about 11377.8302413070. The cubic root of 129455021 is about 505.8708250305.

The spelling of 129455021 in words is "one hundred twenty-nine million, four hundred fifty-five thousand, twenty-one".