1297391618961 has 45 divisors (see below), whose sum is σ = 2045758751883. Its totient is φ = 819282217680.

The previous prime is 1297391618933. The next prime is 1297391618977. The reversal of 1297391618961 is 1698161937921.

The square root of 1297391618961 is 1139031.

It is a perfect power (a square), and thus also a powerful number.

1297391618961 is a `hidden beast` number, since 1 + 2 + 9 + 7 + 3 + 9 + 1 + 618 + 9 + 6 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1220651538561 + 76740080400 = 1104831^2 + 277020^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1297391618961 is a prime.

It is a super-2 number, since 2×1297391618961² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1297396618961) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 194770971 + ... + 194777631.

Almost surely, 2^{1297391618961} is an apocalyptic number.

1297391618961 is the 1139031-st square number.

1297391618961 is the 569516-th centered octagonal number.

It is an amenable number.

1297391618961 is a deficient number, since it is larger than the sum of its proper divisors (748367132922).

1297391618961 is an frugal number, since it uses more digits than its factorization.

1297391618961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13372 (or 6683 counting only the distinct ones).

The product of its digits is 8817984, while the sum is 63.

The spelling of 1297391618961 in words is "one trillion, two hundred ninety-seven billion, three hundred ninety-one million, six hundred eighteen thousand, nine hundred sixty-one".