129790021 has 2 divisors, whose sum is σ = 129790022. Its totient is φ = 129790020.

The previous prime is 129789997. The next prime is 129790061. The reversal of 129790021 is 120097921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 122899396 + 6890625 = 11086^2 + 2625^2 .

It is a cyclic number.

It is not a de Polignac number, because 129790021 - 2¹⁵ = 129757253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129790061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64895010 + 64895011.

It is an arithmetic number, because the mean of its divisors is an integer number (64895011).

Almost surely, 2^129790021 is an apocalyptic number.

It is an amenable number.

129790021 is a deficient number, since it is larger than the sum of its proper divisors (1).

129790021 is an equidigital number, since it uses as much as digits as its factorization.

129790021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 31.

The square root of 129790021 is about 11392.5423413740. The cubic root of 129790021 is about 506.3068085211.

It can be divided in two parts, 1297900 and 21, that added together give a palindrome (1297921).

The spelling of 129790021 in words is "one hundred twenty-nine million, seven hundred ninety thousand, twenty-one".