1315646021 has 2 divisors, whose sum is σ = 1315646022. Its totient is φ = 1315646020.

The previous prime is 1315645993. The next prime is 1315646029. The reversal of 1315646021 is 1206465131.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1117230625 + 198415396 = 33425^2 + 14086^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1315646021 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 (1315646029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 657823010 + 657823011.

It is an arithmetic number, because the mean of its divisors is an integer number (657823011).

Almost surely, 2^1315646021 is an apocalyptic number.

It is an amenable number.

1315646021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1315646021 is an equidigital number, since it uses as much as digits as its factorization.

1315646021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 1315646021 is about 36271.8350928100. The cubic root of 1315646021 is about 1095.7538843558.

The spelling of 1315646021 in words is "one billion, three hundred fifteen million, six hundred forty-six thousand, twenty-one".