6651640181 has 6 divisors (see below), whose sum is σ = 6953416470. Its totient is φ = 6362437928.

The previous prime is 6651640153. The next prime is 6651640199. The reversal of 6651640181 is 1810461566.

It can be written as a sum of positive squares in only one way, i.e., 6325657156 + 325983025 = 79534^2 + 18055^2 .

It is not a de Polignac number, because 6651640181 - 2¹⁰ = 6651639157 is a prime.

It is a super-2 number, since 2×6651640181² = 88488634194987425522, which contains 22 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 (6651610181) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6286466 + ... + 6287523.

It is an arithmetic number, because the mean of its divisors is an integer number (1158902745).

Almost surely, 2^6651640181 is an apocalyptic number.

It is an amenable number.

6651640181 is a deficient number, since it is larger than the sum of its proper divisors (301776289).

6651640181 is a wasteful number, since it uses less digits than its factorization.

6651640181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12574035 (or 12574012 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 38.

The square root of 6651640181 is about 81557.5881264276. The cubic root of 6651640181 is about 1880.6569475823.

The spelling of 6651640181 in words is "six billion, six hundred fifty-one million, six hundred forty thousand, one hundred eighty-one".