80621991 has 24 divisors (see below), whose sum is σ = 118778400. Its totient is φ = 52684800.

The previous prime is 80621987. The next prime is 80621993. The reversal of 80621991 is 19912608.

It is not a de Polignac number, because 80621991 - 2² = 80621987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (80621993) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 179335 + ... + 179783.

It is an arithmetic number, because the mean of its divisors is an integer number (4949100).

Almost surely, 2^80621991 is an apocalyptic number.

80621991 is a deficient number, since it is larger than the sum of its proper divisors (38156409).

80621991 is a wasteful number, since it uses less digits than its factorization.

80621991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 807 (or 804 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 80621991 is about 8978.9749414953. The cubic root of 80621991 is about 432.0007555285. Note that the first 3 decimals are identical.

The spelling of 80621991 in words is "eighty million, six hundred twenty-one thousand, nine hundred ninety-one".