81765319 has 6 divisors (see below), whose sum is σ = 82304600. Its totient is φ = 81227520.

The previous prime is 81765311. The next prime is 81765323. The reversal of 81765319 is 91356718.

It is not a de Polignac number, because 81765319 - 2³ = 81765311 is a prime.

It is a super-2 number, since 2×81765319² = 13371134782343522, which contains 22 as substring.

It is a Duffinian number.

Its product of digits (45360) is a multiple of the sum of its prime divisors (840).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81765311) 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 5 ways as a sum of consecutive naturals, for example, 127239 + ... + 127879.

Almost surely, 2^81765319 is an apocalyptic number.

81765319 is a deficient number, since it is larger than the sum of its proper divisors (539281).

81765319 is an frugal number, since it uses more digits than its factorization.

81765319 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1481 (or 840 counting only the distinct ones).

The product of its digits is 45360, while the sum is 40.

The square root of 81765319 is about 9042.4177629658. The cubic root of 81765319 is about 434.0332943233.

The spelling of 81765319 in words is "eighty-one million, seven hundred sixty-five thousand, three hundred nineteen".