82638781 has 4 divisors (see below), whose sum is σ = 83133792. Its totient is φ = 82143772.

The previous prime is 82638769. The next prime is 82638799. The reversal of 82638781 is 18783628.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 82638781 - 2⁵ = 82638749 is a prime.

It is a super-2 number, since 2×82638781² = 13658336250331922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82633781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 247255 + ... + 247588.

It is an arithmetic number, because the mean of its divisors is an integer number (20783448).

Almost surely, 2^82638781 is an apocalyptic number.

It is an amenable number.

82638781 is a deficient number, since it is larger than the sum of its proper divisors (495011).

82638781 is a wasteful number, since it uses less digits than its factorization.

82638781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495010.

The product of its digits is 129024, while the sum is 43.

The square root of 82638781 is about 9090.5874947662. The cubic root of 82638781 is about 435.5733506278.

The spelling of 82638781 in words is "eighty-two million, six hundred thirty-eight thousand, seven hundred eighty-one".