1815637361 has 2 divisors, whose sum is σ = 1815637362. Its totient is φ = 1815637360.

The previous prime is 1815637211. The next prime is 1815637387. The reversal of 1815637361 is 1637365181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1758544225 + 57093136 = 41935^2 + 7556^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1815637361 is a prime.

It is not a weakly prime, because it can be changed into another prime (1815634361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 907818680 + 907818681.

It is an arithmetic number, because the mean of its divisors is an integer number (907818681).

Almost surely, 2^1815637361 is an apocalyptic number.

It is an amenable number.

1815637361 is a deficient number, since it is larger than the sum of its proper divisors (1).

1815637361 is an equidigital number, since it uses as much as digits as its factorization.

1815637361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 41.

The square root of 1815637361 is about 42610.2964199969. The cubic root of 1815637361 is about 1219.9528247010.

The spelling of 1815637361 in words is "one billion, eight hundred fifteen million, six hundred thirty-seven thousand, three hundred sixty-one".