1172651561 has 2 divisors, whose sum is σ = 1172651562. Its totient is φ = 1172651560.

The previous prime is 1172651533. The next prime is 1172651563. The reversal of 1172651561 is 1651562711.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1172651536 + 25 = 34244^2 + 5^2 .

It is a cyclic number.

It is not a de Polignac number, because 1172651561 - 2¹⁰ = 1172650537 is a prime.

It is a super-2 number, since 2×1172651561² = 2750223367031473442, which contains 22 as substring.

Together with 1172651563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1172651563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 586325780 + 586325781.

It is an arithmetic number, because the mean of its divisors is an integer number (586325781).

Almost surely, 2^1172651561 is an apocalyptic number.

It is an amenable number.

1172651561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1172651561 is an equidigital number, since it uses as much as digits as its factorization.

1172651561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12600, while the sum is 35.

The square root of 1172651561 is about 34244.0003650274. Note that the first 3 decimals coincide. The cubic root of 1172651561 is about 1054.5236608860.

The spelling of 1172651561 in words is "one billion, one hundred seventy-two million, six hundred fifty-one thousand, five hundred sixty-one".