129821647 has 2 divisors, whose sum is σ = 129821648. Its totient is φ = 129821646.

The previous prime is 129821617. The next prime is 129821651. The reversal of 129821647 is 746128921.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-129821647 is a prime.

It is equal to p_7368754 and since 129821647 and 7368754 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129821617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64910823 + 64910824.

It is an arithmetic number, because the mean of its divisors is an integer number (64910824).

Almost surely, 2^129821647 is an apocalyptic number.

129821647 is a deficient number, since it is larger than the sum of its proper divisors (1).

129821647 is an equidigital number, since it uses as much as digits as its factorization.

129821647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 40.

The square root of 129821647 is about 11393.9302701043. The cubic root of 129821647 is about 506.3479291933.

The spelling of 129821647 in words is "one hundred twenty-nine million, eight hundred twenty-one thousand, six hundred forty-seven".