81864507 has 8 divisors (see below), whose sum is σ = 109203984. Its totient is φ = 54550688.

The previous prime is 81864473. The next prime is 81864509. The reversal of 81864507 is 70546818.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81864507 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81864509) 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, 3013 + ... + 13145.

It is an arithmetic number, because the mean of its divisors is an integer number (13650498).

Almost surely, 2^81864507 is an apocalyptic number.

81864507 is a deficient number, since it is larger than the sum of its proper divisors (27339477).

81864507 is a wasteful number, since it uses less digits than its factorization.

81864507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12829.

The product of its (nonzero) digits is 53760, while the sum is 39.

The square root of 81864507 is about 9047.9006957415. The cubic root of 81864507 is about 434.2087293307.

The spelling of 81864507 in words is "eighty-one million, eight hundred sixty-four thousand, five hundred seven".