6660151661 has 4 divisors (see below), whose sum is σ = 6660318300. Its totient is φ = 6659985024.

The previous prime is 6660151651. The next prime is 6660151669. The reversal of 6660151661 is 1661510666.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1661510666 = 2 ⋅830755333.

It can be written as a sum of positive squares in 2 ways, for example, as 2841529636 + 3818622025 = 53306^2 + 61795^2 .

It is a cyclic number.

It is not a de Polignac number, because 6660151661 - 2¹⁸ = 6659889517 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 (6660151669) 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, 16475 + ... + 116583.

It is an arithmetic number, because the mean of its divisors is an integer number (1665079575).

Almost surely, 2^6660151661 is an apocalyptic number.

It is an amenable number.

6660151661 is a deficient number, since it is larger than the sum of its proper divisors (166639).

6660151661 is a wasteful number, since it uses less digits than its factorization.

6660151661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166638.

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 6660151661 is about 81609.7522419962. The cubic root of 6660151661 is about 1881.4587724347.

The spelling of 6660151661 in words is "six billion, six hundred sixty million, one hundred fifty-one thousand, six hundred sixty-one".