5656501661 has 4 divisors (see below), whose sum is σ = 5692530492. Its totient is φ = 5620472832.

The previous prime is 5656501657. The next prime is 5656501679. The reversal of 5656501661 is 1661056565.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4069674436 + 1586827225 = 63794^2 + 39835^2 .

It is a cyclic number.

It is not a de Polignac number, because 5656501661 - 2² = 5656501657 is a prime.

It is a super-2 number, since 2×5656501661² = 63992022081791517842, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5656501861) 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, 18014180 + ... + 18014493.

It is an arithmetic number, because the mean of its divisors is an integer number (1423132623).

Almost surely, 2^5656501661 is an apocalyptic number.

It is an amenable number.

5656501661 is a deficient number, since it is larger than the sum of its proper divisors (36028831).

5656501661 is a wasteful number, since it uses less digits than its factorization.

5656501661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36028830.

The product of its (nonzero) digits is 162000, while the sum is 41.

The square root of 5656501661 is about 75209.7178627869. The cubic root of 5656501661 is about 1781.7604160396.

The spelling of 5656501661 in words is "five billion, six hundred fifty-six million, five hundred one thousand, six hundred sixty-one".