80999857 has 2 divisors, whose sum is σ = 80999858. Its totient is φ = 80999856.

The previous prime is 80999839. The next prime is 80999881. The reversal of 80999857 is 75899908.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52867441 + 28132416 = 7271^2 + 5304^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-80999857 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 80999798 and 80999807.

It is not a weakly prime, because it can be changed into another prime (80999257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40499928 + 40499929.

It is an arithmetic number, because the mean of its divisors is an integer number (40499929).

Almost surely, 2^80999857 is an apocalyptic number.

It is an amenable number.

80999857 is a deficient number, since it is larger than the sum of its proper divisors (1).

80999857 is an equidigital number, since it uses as much as digits as its factorization.

80999857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1632960, while the sum is 55.

The square root of 80999857 is about 8999.9920555520. The cubic root of 80999857 is about 432.6746164727.

It can be divided in two parts, 8099 and 9857, that added together give a square (17956 = 134²).

The spelling of 80999857 in words is "eighty million, nine hundred ninety-nine thousand, eight hundred fifty-seven".