80643661 has 12 divisors (see below), whose sum is σ = 94213020. Its totient is φ = 68826240.

The previous prime is 80643659. The next prime is 80643671. The reversal of 80643661 is 16634608.

It can be written as a sum of positive squares in 2 ways, for example, as 52490025 + 28153636 = 7245^2 + 5306^2 .

It is not a de Polignac number, because 80643661 - 2¹ = 80643659 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 (80643601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8395 + ... + 15223.

It is an arithmetic number, because the mean of its divisors is an integer number (7851085).

Almost surely, 2^80643661 is an apocalyptic number.

It is an amenable number.

80643661 is a deficient number, since it is larger than the sum of its proper divisors (13569359).

80643661 is a wasteful number, since it uses less digits than its factorization.

80643661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7084 (or 7077 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 80643661 is about 8980.1815683203. The cubic root of 80643661 is about 432.0394572013.

The spelling of 80643661 in words is "eighty million, six hundred forty-three thousand, six hundred sixty-one".