81398268 has 36 divisors (see below), whose sum is σ = 235151280. Its totient is φ = 23256576.

The previous prime is 81398267. The next prime is 81398323. The reversal of 81398268 is 86289318.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81398263) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 161253 + ... + 161756.

It is an arithmetic number, because the mean of its divisors is an integer number (6531980).

Almost surely, 2^81398268 is an apocalyptic number.

It is an amenable number.

81398268 is an abundant number, since it is smaller than the sum of its proper divisors (153753012).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81398268 is a wasteful number, since it uses less digits than its factorization.

81398268 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323026 (or 323021 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 81398268 is about 9022.0988688885. The cubic root of 81398268 is about 433.3828500943.

The spelling of 81398268 in words is "eighty-one million, three hundred ninety-eight thousand, two hundred sixty-eight".