81306987 has 8 divisors (see below), whose sum is σ = 108490704. Its totient is φ = 54163968.

The previous prime is 81306959. The next prime is 81307021. The reversal of 81306987 is 78960318.

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

It is not a de Polignac number, because 81306987 - 2⁷ = 81306859 is a prime.

It is a super-2 number, since 2×81306987² = 13221652270036338, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81306487) 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, 5158 + ... + 13755.

It is an arithmetic number, because the mean of its divisors is an integer number (13561338).

Almost surely, 2^81306987 is an apocalyptic number.

81306987 is a deficient number, since it is larger than the sum of its proper divisors (27183717).

81306987 is a wasteful number, since it uses less digits than its factorization.

81306987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20349.

The product of its (nonzero) digits is 72576, while the sum is 42.

The square root of 81306987 is about 9017.0387045859. The cubic root of 81306987 is about 433.2207892476.

The spelling of 81306987 in words is "eighty-one million, three hundred six thousand, nine hundred eighty-seven".