129193021 has 2 divisors, whose sum is σ = 129193022. Its totient is φ = 129193020.

The previous prime is 129193019. The next prime is 129193049. The reversal of 129193021 is 120391921.

It is an a-pointer prime, because the next prime (129193049) can be obtained adding 129193021 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 84824100 + 44368921 = 9210^2 + 6661^2 .

It is a cyclic number.

It is not a de Polignac number, because 129193021 - 2¹ = 129193019 is a prime.

Together with 129193019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129193321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64596510 + 64596511.

It is an arithmetic number, because the mean of its divisors is an integer number (64596511).

Almost surely, 2^129193021 is an apocalyptic number.

It is an amenable number.

129193021 is a deficient number, since it is larger than the sum of its proper divisors (1).

129193021 is an equidigital number, since it uses as much as digits as its factorization.

129193021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 129193021 is about 11366.3107911054. The cubic root of 129193021 is about 505.5293224528.

The spelling of 129193021 in words is "one hundred twenty-nine million, one hundred ninety-three thousand, twenty-one".