81229865 has 8 divisors (see below), whose sum is σ = 99550080. Its totient is φ = 63601072.

The previous prime is 81229861. The next prime is 81229877. The reversal of 81229865 is 56892218.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81229865 - 2² = 81229861 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81229861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 172595 + ... + 173064.

It is an arithmetic number, because the mean of its divisors is an integer number (12443760).

Almost surely, 2^81229865 is an apocalyptic number.

It is an amenable number.

81229865 is a deficient number, since it is larger than the sum of its proper divisors (18320215).

81229865 is a wasteful number, since it uses less digits than its factorization.

81229865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345711.

The product of its digits is 69120, while the sum is 41.

The square root of 81229865 is about 9012.7612306107. The cubic root of 81229865 is about 433.0837718184.

The spelling of 81229865 in words is "eighty-one million, two hundred twenty-nine thousand, eight hundred sixty-five".