81862831 has 2 divisors, whose sum is σ = 81862832. Its totient is φ = 81862830.

The previous prime is 81862813. The next prime is 81862873. The reversal of 81862831 is 13826818.

Together with previous prime (81862813) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81862831 - 2¹¹ = 81860783 is a prime.

It is a super-2 number, since 2×81862831² = 13403046198669122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81862801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40931415 + 40931416.

It is an arithmetic number, because the mean of its divisors is an integer number (40931416).

Almost surely, 2^81862831 is an apocalyptic number.

81862831 is a deficient number, since it is larger than the sum of its proper divisors (1).

81862831 is an equidigital number, since it uses as much as digits as its factorization.

81862831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18432, while the sum is 37.

The square root of 81862831 is about 9047.8080770980. The cubic root of 81862831 is about 434.2057661467.

The spelling of 81862831 in words is "eighty-one million, eight hundred sixty-two thousand, eight hundred thirty-one".