80691021 has 24 divisors (see below), whose sum is σ = 121806360. Its totient is φ = 51408000.

The previous prime is 80691019. The next prime is 80691053. The reversal of 80691021 is 12019608.

It can be written as a sum of positive squares in 4 ways, for example, as 55800900 + 24890121 = 7470^2 + 4989^2 .

It is not a de Polignac number, because 80691021 - 2¹ = 80691019 is a prime.

It is a super-2 number, since 2×80691021² = 13022081740044882, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (80691421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24831 + ... + 27891.

It is an arithmetic number, because the mean of its divisors is an integer number (5075265).

Almost surely, 2^80691021 is an apocalyptic number.

It is an amenable number.

80691021 is a deficient number, since it is larger than the sum of its proper divisors (41115339).

80691021 is a wasteful number, since it uses less digits than its factorization.

80691021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3197 (or 3194 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 80691021 is about 8982.8180990155. The cubic root of 80691021 is about 432.1240159638.

The spelling of 80691021 in words is "eighty million, six hundred ninety-one thousand, twenty-one".