1161330661 has 4 divisors (see below), whose sum is σ = 1186039872. Its totient is φ = 1136621452.

The previous prime is 1161330641. The next prime is 1161330671. The reversal of 1161330661 is 1660331611.

It is a happy number.

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: 1660331611 = 61 ⋅27218551.

It is a cyclic number.

It is not a de Polignac number, because 1161330661 - 2¹⁹ = 1160806373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1161330641) 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, 12354535 + ... + 12354628.

It is an arithmetic number, because the mean of its divisors is an integer number (296509968).

Almost surely, 2^1161330661 is an apocalyptic number.

It is an amenable number.

1161330661 is a deficient number, since it is larger than the sum of its proper divisors (24709211).

1161330661 is an equidigital number, since it uses as much as digits as its factorization.

1161330661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24709210.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 1161330661 is about 34078.3019089860. The cubic root of 1161330661 is about 1051.1191878961.

The spelling of 1161330661 in words is "one billion, one hundred sixty-one million, three hundred thirty thousand, six hundred sixty-one".