129421639 has 2 divisors, whose sum is σ = 129421640. Its totient is φ = 129421638.

The previous prime is 129421609. The next prime is 129421723. The reversal of 129421639 is 936124921.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 129421639 - 2¹³ = 129413447 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 129421598 and 129421607.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129421609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64710819 + 64710820.

It is an arithmetic number, because the mean of its divisors is an integer number (64710820).

Almost surely, 2^129421639 is an apocalyptic number.

129421639 is a deficient number, since it is larger than the sum of its proper divisors (1).

129421639 is an equidigital number, since it uses as much as digits as its factorization.

129421639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 37.

The square root of 129421639 is about 11376.3631710666. The cubic root of 129421639 is about 505.8273390602.

The spelling of 129421639 in words is "one hundred twenty-nine million, four hundred twenty-one thousand, six hundred thirty-nine".