6659633861 has 4 divisors (see below), whose sum is σ = 6660988812. Its totient is φ = 6658278912.

The previous prime is 6659633837. The next prime is 6659633879. The reversal of 6659633861 is 1683369566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1683369566 = 2 ⋅841684783.

It can be written as a sum of positive squares in 2 ways, for example, as 1429596100 + 5230037761 = 37810^2 + 72319^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6659633861 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 (6659633161) 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, 670076 + ... + 679941.

It is an arithmetic number, because the mean of its divisors is an integer number (1665247203).

Almost surely, 2^6659633861 is an apocalyptic number.

It is an amenable number.

6659633861 is a deficient number, since it is larger than the sum of its proper divisors (1354951).

6659633861 is a wasteful number, since it uses less digits than its factorization.

6659633861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1354950.

The product of its digits is 4199040, while the sum is 53.

The square root of 6659633861 is about 81606.5797653596. The cubic root of 6659633861 is about 1881.4100125540.

The spelling of 6659633861 in words is "six billion, six hundred fifty-nine million, six hundred thirty-three thousand, eight hundred sixty-one".