1215690257 has 2 divisors, whose sum is σ = 1215690258. Its totient is φ = 1215690256.

The previous prime is 1215690253. The next prime is 1215690263. The reversal of 1215690257 is 7520965121.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 790959376 + 424730881 = 28124^2 + 20609^2 .

It is a cyclic number.

It is not a de Polignac number, because 1215690257 - 2² = 1215690253 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1215690257.

It is not a weakly prime, because it can be changed into another prime (1215690251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607845128 + 607845129.

It is an arithmetic number, because the mean of its divisors is an integer number (607845129).

Almost surely, 2^1215690257 is an apocalyptic number.

It is an amenable number.

1215690257 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215690257 is an equidigital number, since it uses as much as digits as its factorization.

1215690257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 37800, while the sum is 38.

The square root of 1215690257 is about 34866.7500206142. The cubic root of 1215690257 is about 1067.2700247388.

The spelling of 1215690257 in words is "one billion, two hundred fifteen million, six hundred ninety thousand, two hundred fifty-seven".