5966961661 has 4 divisors (see below), whose sum is σ = 5978920000. Its totient is φ = 5955003324.

The previous prime is 5966961653. The next prime is 5966961797. The reversal of 5966961661 is 1661696695.

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.

It is a cyclic number.

It is not a de Polignac number, because 5966961661 - 2³ = 5966961653 is a prime.

It is a super-3 number, since 3×5966961661³ (a number of 30 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5966961601) 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, 5978421 + ... + 5979418.

It is an arithmetic number, because the mean of its divisors is an integer number (1494730000).

Almost surely, 2^5966961661 is an apocalyptic number.

It is an amenable number.

5966961661 is a deficient number, since it is larger than the sum of its proper divisors (11958339).

5966961661 is a wasteful number, since it uses less digits than its factorization.

5966961661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11958338.

The product of its digits is 3149280, while the sum is 55.

The square root of 5966961661 is about 77246.1109765404. The cubic root of 5966961661 is about 1813.7791941728.

The spelling of 5966961661 in words is "five billion, nine hundred sixty-six million, nine hundred sixty-one thousand, six hundred sixty-one".