82919781 has 80 divisors (see below), whose sum is σ = 153331200. Its totient is φ = 43600032.

The previous prime is 82919777. The next prime is 82919789. The reversal of 82919781 is 18791928.

It is not a de Polignac number, because 82919781 - 2² = 82919777 is a prime.

It is a super-2 number, since 2×82919781² = 13751380162175922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82919789) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 463150 + ... + 463328.

It is an arithmetic number, because the mean of its divisors is an integer number (1916640).

Almost surely, 2^82919781 is an apocalyptic number.

82919781 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

82919781 is a deficient number, since it is larger than the sum of its proper divisors (70411419).

82919781 is a wasteful number, since it uses less digits than its factorization.

82919781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260 (or 251 counting only the distinct ones).

The product of its digits is 72576, while the sum is 45.

The square root of 82919781 is about 9106.0299252748. The cubic root of 82919781 is about 436.0664913463.

The spelling of 82919781 in words is "eighty-two million, nine hundred nineteen thousand, seven hundred eighty-one".