81285707 has 8 divisors (see below), whose sum is σ = 84542400. Its totient is φ = 78084864.

The previous prime is 81285697. The next prime is 81285727. The reversal of 81285707 is 70758218.

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

It is not a de Polignac number, because 81285707 - 2¹⁶ = 81220171 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81285727) 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, 10982 + ... + 16827.

It is an arithmetic number, because the mean of its divisors is an integer number (10567800).

Almost surely, 2^81285707 is an apocalyptic number.

81285707 is a deficient number, since it is larger than the sum of its proper divisors (3256693).

81285707 is a wasteful number, since it uses less digits than its factorization.

81285707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27925.

The product of its (nonzero) digits is 31360, while the sum is 38.

The square root of 81285707 is about 9015.8586390870. The cubic root of 81285707 is about 433.1829911726.

The spelling of 81285707 in words is "eighty-one million, two hundred eighty-five thousand, seven hundred seven".