80817661 has 2 divisors, whose sum is σ = 80817662. Its totient is φ = 80817660.

The previous prime is 80817641. The next prime is 80817673. The reversal of 80817661 is 16671808.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75951225 + 4866436 = 8715^2 + 2206^2 .

It is a cyclic number.

It is not a de Polignac number, because 80817661 - 2¹⁷ = 80686589 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 80817661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (80817641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40408830 + 40408831.

It is an arithmetic number, because the mean of its divisors is an integer number (40408831).

Almost surely, 2^80817661 is an apocalyptic number.

It is an amenable number.

80817661 is a deficient number, since it is larger than the sum of its proper divisors (1).

80817661 is an equidigital number, since it uses as much as digits as its factorization.

80817661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 80817661 is about 8989.8643482535. The cubic root of 80817661 is about 432.3499625470.

The spelling of 80817661 in words is "eighty million, eight hundred seventeen thousand, six hundred sixty-one".