81073791 has 24 divisors (see below), whose sum is σ = 124284160. Its totient is φ = 52785432.

The previous prime is 81073789. The next prime is 81073801. The reversal of 81073791 is 19737018.

It is not a de Polignac number, because 81073791 - 2¹ = 81073789 is a prime.

It is a super-2 number, since 2×81073791² = 13145919174223362, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81073691) 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, 6570 + ... + 14328.

Almost surely, 2^81073791 is an apocalyptic number.

81073791 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81073791 is a deficient number, since it is larger than the sum of its proper divisors (43210369).

81073791 is an equidigital number, since it uses as much as digits as its factorization.

81073791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7817 (or 7805 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 36.

The square root of 81073791 is about 9004.0985667639. The cubic root of 81073791 is about 432.8062201498.

The spelling of 81073791 in words is "eighty-one million, seventy-three thousand, seven hundred ninety-one".