81804907 has 4 divisors (see below), whose sum is σ = 81944856. Its totient is φ = 81664960.

The previous prime is 81804893. The next prime is 81804949. The reversal of 81804907 is 70940818.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81804907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81804967) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69094 + ... + 70267.

It is an arithmetic number, because the mean of its divisors is an integer number (20486214).

Almost surely, 2^81804907 is an apocalyptic number.

81804907 is a deficient number, since it is larger than the sum of its proper divisors (139949).

81804907 is a wasteful number, since it uses less digits than its factorization.

81804907 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139948.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 81804907 is about 9044.6065143819. The cubic root of 81804907 is about 434.1033310983.

The spelling of 81804907 in words is "eighty-one million, eight hundred four thousand, nine hundred seven".