82127781 has 6 divisors (see below), whose sum is σ = 118629030. Its totient is φ = 54751848.

The previous prime is 82127767. The next prime is 82127789. The reversal of 82127781 is 18772128.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 79121025 + 3006756 = 8895^2 + 1734^2 .

It is not a de Polignac number, because 82127781 - 2⁷ = 82127653 is a prime.

It is a super-2 number, since 2×82127781² = 13489944823967922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82127789) 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, 4562646 + ... + 4562663.

It is an arithmetic number, because the mean of its divisors is an integer number (19771505).

Almost surely, 2^82127781 is an apocalyptic number.

It is an amenable number.

82127781 is a deficient number, since it is larger than the sum of its proper divisors (36501249).

82127781 is a wasteful number, since it uses less digits than its factorization.

82127781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9125315 (or 9125312 counting only the distinct ones).

The product of its digits is 12544, while the sum is 36.

The square root of 82127781 is about 9062.4379170287. The cubic root of 82127781 is about 434.6736990150.

The spelling of 82127781 in words is "eighty-two million, one hundred twenty-seven thousand, seven hundred eighty-one".