81249867 has 12 divisors (see below), whose sum is σ = 117621504. Its totient is φ = 54046320.

The previous prime is 81249863. The next prime is 81249877. The reversal of 81249867 is 76894218.

It is not a de Polignac number, because 81249867 - 2² = 81249863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81249863) 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, 5643 + ... + 13940.

It is an arithmetic number, because the mean of its divisors is an integer number (9801792).

Almost surely, 2^81249867 is an apocalyptic number.

81249867 is a deficient number, since it is larger than the sum of its proper divisors (36371637).

81249867 is a wasteful number, since it uses less digits than its factorization.

81249867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20050 (or 20047 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 81249867 is about 9013.8708111443. The cubic root of 81249867 is about 433.1193163425.

The spelling of 81249867 in words is "eighty-one million, two hundred forty-nine thousand, eight hundred sixty-seven".