82125781 has 2 divisors, whose sum is σ = 82125782. Its totient is φ = 82125780.

The previous prime is 82125773. The next prime is 82125821. The reversal of 82125781 is 18752128.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57623281 + 24502500 = 7591^2 + 4950^2 .

It is a cyclic number.

It is not a de Polignac number, because 82125781 - 2³ = 82125773 is a prime.

It is a super-2 number, since 2×82125781² = 13489287809719922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (82125721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41062890 + 41062891.

It is an arithmetic number, because the mean of its divisors is an integer number (41062891).

Almost surely, 2^82125781 is an apocalyptic number.

It is an amenable number.

82125781 is a deficient number, since it is larger than the sum of its proper divisors (1).

82125781 is an equidigital number, since it uses as much as digits as its factorization.

82125781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8960, while the sum is 34.

The square root of 82125781 is about 9062.3275707734. The cubic root of 82125781 is about 434.6701705522.

The spelling of 82125781 in words is "eighty-two million, one hundred twenty-five thousand, seven hundred eighty-one".