81539983 has 6 divisors (see below), whose sum is σ = 93215864. Its totient is φ = 69870936.

The previous prime is 81539977. The next prime is 81539987. The reversal of 81539983 is 38993518.

It is not a de Polignac number, because 81539983 - 2¹⁷ = 81408911 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81539987) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 22185 + ... + 25597.

Almost surely, 2^81539983 is an apocalyptic number.

81539983 is a deficient number, since it is larger than the sum of its proper divisors (11675881).

81539983 is an frugal number, since it uses more digits than its factorization.

81539983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6833 (or 3420 counting only the distinct ones).

The product of its digits is 233280, while the sum is 46.

The square root of 81539983 is about 9029.9492246634. The cubic root of 81539983 is about 433.6342118827.

The spelling of 81539983 in words is "eighty-one million, five hundred thirty-nine thousand, nine hundred eighty-three".