129223521 has 12 divisors (see below), whose sum is σ = 213321472. Its totient is φ = 73841976.

The previous prime is 129223519. The next prime is 129223553. The reversal of 129223521 is 125322921.

It is a happy number.

It is not a de Polignac number, because 129223521 - 2¹ = 129223519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (129223571) 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, 1025521 + ... + 1025646.

Almost surely, 2^129223521 is an apocalyptic number.

It is an amenable number.

129223521 is a deficient number, since it is larger than the sum of its proper divisors (84097951).

129223521 is a wasteful number, since it uses less digits than its factorization.

129223521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2051180 (or 2051177 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 129223521 is about 11367.6523961634. The cubic root of 129223521 is about 505.5691012557.

The spelling of 129223521 in words is "one hundred twenty-nine million, two hundred twenty-three thousand, five hundred twenty-one".