1156072561 has 4 divisors (see below), whose sum is σ = 1321225792. Its totient is φ = 990919332.

The previous prime is 1156072543. The next prime is 1156072579. The reversal of 1156072561 is 1652706511.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1652706511 = 229 ⋅7217059.

It is an interprime number because it is at equal distance from previous prime (1156072543) and next prime (1156072579).

It is a cyclic number.

It is not a de Polignac number, because 1156072561 - 2¹⁷ = 1155941489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1156072261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82576605 + ... + 82576618.

It is an arithmetic number, because the mean of its divisors is an integer number (330306448).

Almost surely, 2^1156072561 is an apocalyptic number.

It is an amenable number.

1156072561 is a deficient number, since it is larger than the sum of its proper divisors (165153231).

1156072561 is an equidigital number, since it uses as much as digits as its factorization.

1156072561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165153230.

The product of its (nonzero) digits is 12600, while the sum is 34.

The square root of 1156072561 is about 34001.0670567851. The cubic root of 1156072561 is about 1049.5304207147.

The spelling of 1156072561 in words is "one billion, one hundred fifty-six million, seventy-two thousand, five hundred sixty-one".