1215716261 has 2 divisors, whose sum is σ = 1215716262. Its totient is φ = 1215716260.

The previous prime is 1215716233. The next prime is 1215716303. The reversal of 1215716261 is 1626175121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 929091361 + 286624900 = 30481^2 + 16930^2 .

It is an emirp because it is prime and its reverse (1626175121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1215716261 - 2²² = 1211521957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1215716861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607858130 + 607858131.

It is an arithmetic number, because the mean of its divisors is an integer number (607858131).

Almost surely, 2^1215716261 is an apocalyptic number.

It is an amenable number.

1215716261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215716261 is an equidigital number, since it uses as much as digits as its factorization.

1215716261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5040, while the sum is 32.

The square root of 1215716261 is about 34867.1229240383. The cubic root of 1215716261 is about 1067.2776344326.

The spelling of 1215716261 in words is "one billion, two hundred fifteen million, seven hundred sixteen thousand, two hundred sixty-one".