81368385 has 32 divisors (see below), whose sum is σ = 149134080. Its totient is φ = 37110528.

The previous prime is 81368383. The next prime is 81368387. The reversal of 81368385 is 58386318.

It is an interprime number because it is at equal distance from previous prime (81368383) and next prime (81368387).

It is not a de Polignac number, because 81368385 - 2¹ = 81368383 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81368383) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 73899 + ... + 74991.

It is an arithmetic number, because the mean of its divisors is an integer number (4660440).

Almost surely, 2^81368385 is an apocalyptic number.

It is an amenable number.

81368385 is a deficient number, since it is larger than the sum of its proper divisors (67765695).

81368385 is a wasteful number, since it uses less digits than its factorization.

81368385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1817.

The product of its digits is 138240, while the sum is 42.

The square root of 81368385 is about 9020.4426166347. The cubic root of 81368385 is about 433.3298089786.

The spelling of 81368385 in words is "eighty-one million, three hundred sixty-eight thousand, three hundred eighty-five".