81236489 has 8 divisors (see below), whose sum is σ = 86130720. Its totient is φ = 76355136.

The previous prime is 81236471. The next prime is 81236513. The reversal of 81236489 is 98463218.

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 81236489 - 2¹⁶ = 81170953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81236459) 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, 11822 + ... + 17384.

It is an arithmetic number, because the mean of its divisors is an integer number (10766340).

Almost surely, 2^81236489 is an apocalyptic number.

It is an amenable number.

81236489 is a deficient number, since it is larger than the sum of its proper divisors (4894231).

81236489 is a wasteful number, since it uses less digits than its factorization.

81236489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6439.

The product of its digits is 82944, while the sum is 41.

The square root of 81236489 is about 9013.1287020657. The cubic root of 81236489 is about 433.0955436338.

The spelling of 81236489 in words is "eighty-one million, two hundred thirty-six thousand, four hundred eighty-nine".