81865351 has 2 divisors, whose sum is σ = 81865352. Its totient is φ = 81865350.

The previous prime is 81865331. The next prime is 81865361. The reversal of 81865351 is 15356818.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81865351 - 2¹¹ = 81863303 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81865351.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81865321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40932675 + 40932676.

It is an arithmetic number, because the mean of its divisors is an integer number (40932676).

Almost surely, 2^81865351 is an apocalyptic number.

81865351 is a deficient number, since it is larger than the sum of its proper divisors (1).

81865351 is an equidigital number, since it uses as much as digits as its factorization.

81865351 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28800, while the sum is 37.

The square root of 81865351 is about 9047.9473362747. The cubic root of 81865351 is about 434.2102215155.

The spelling of 81865351 in words is "eighty-one million, eight hundred sixty-five thousand, three hundred fifty-one".