81297783 has 16 divisors (see below), whose sum is σ = 137647360. Its totient is φ = 46455768.

The previous prime is 81297781. The next prime is 81297787. The reversal of 81297783 is 38779218.

It is not a de Polignac number, because 81297783 - 2¹ = 81297781 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81297781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 214885 + ... + 215262.

It is an arithmetic number, because the mean of its divisors is an integer number (8602960).

Almost surely, 2^81297783 is an apocalyptic number.

81297783 is a deficient number, since it is larger than the sum of its proper divisors (56349577).

81297783 is a wasteful number, since it uses less digits than its factorization.

81297783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430163 (or 430157 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 81297783 is about 9016.5283230299. The cubic root of 81297783 is about 433.2044416791.

The spelling of 81297783 in words is "eighty-one million, two hundred ninety-seven thousand, seven hundred eighty-three".