1320961747561 has 9 divisors (see below), whose sum is σ = 1357672033431. Its totient is φ = 1285218702792.

The previous prime is 1320961747543. The next prime is 1320961747613. The reversal of 1320961747561 is 1657471690231.

The square root of 1320961747561 is 1149331.

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

It can be written as a sum of positive squares in only one way, i.e., 1182014712025 + 138947035536 = 1087205^2 + 372756^2 .

It is not a de Polignac number, because 1320961747561 - 2³¹ = 1318814263913 is a prime.

It is a super-2 number, since 2×1320961747561² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1320961747499 and 1320961747508.

It is not an unprimeable number, because it can be changed into a prime (1320961747661) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 42509716 + ... + 42540778.

It is an arithmetic number, because the mean of its divisors is an integer number (150852448159).

Almost surely, 2^{1320961747561} is an apocalyptic number.

1320961747561 is the 1149331-st square number.

1320961747561 is the 574666-th centered octagonal number.

It is an amenable number.

1320961747561 is a deficient number, since it is larger than the sum of its proper divisors (36710285870).

1320961747561 is an frugal number, since it uses more digits than its factorization.

1320961747561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62200 (or 31100 counting only the distinct ones).

The product of its (nonzero) digits is 1905120, while the sum is 52.

The spelling of 1320961747561 in words is "one trillion, three hundred twenty billion, nine hundred sixty-one million, seven hundred forty-seven thousand, five hundred sixty-one".