81395887 has 2 divisors, whose sum is σ = 81395888. Its totient is φ = 81395886.

The previous prime is 81395857. The next prime is 81395921. The reversal of 81395887 is 78859318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81395887 - 2²³ = 73007279 is a prime.

It is a super-3 number, since 3×81395887³ (a number of 25 digits) contains 333 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81395887.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81395807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40697943 + 40697944.

It is an arithmetic number, because the mean of its divisors is an integer number (40697944).

Almost surely, 2^81395887 is an apocalyptic number.

81395887 is a deficient number, since it is larger than the sum of its proper divisors (1).

81395887 is an equidigital number, since it uses as much as digits as its factorization.

81395887 is an evil number, because the sum of its binary digits is even.

The product of its digits is 483840, while the sum is 49.

The square root of 81395887 is about 9021.9669141490. The cubic root of 81395887 is about 433.3786243917.

The spelling of 81395887 in words is "eighty-one million, three hundred ninety-five thousand, eight hundred eighty-seven".