129284021 has 2 divisors, whose sum is σ = 129284022. Its totient is φ = 129284020.

The previous prime is 129284017. The next prime is 129284033. The reversal of 129284021 is 120482921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121660900 + 7623121 = 11030^2 + 2761^2 .

It is a cyclic number.

It is not a de Polignac number, because 129284021 - 2² = 129284017 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (129284821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64642010 + 64642011.

It is an arithmetic number, because the mean of its divisors is an integer number (64642011).

Almost surely, 2^129284021 is an apocalyptic number.

It is an amenable number.

129284021 is a deficient number, since it is larger than the sum of its proper divisors (1).

129284021 is an equidigital number, since it uses as much as digits as its factorization.

129284021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 129284021 is about 11370.3131443246. The cubic root of 129284021 is about 505.6479882318.

The spelling of 129284021 in words is "one hundred twenty-nine million, two hundred eighty-four thousand, twenty-one".