81456789 has 8 divisors (see below), whose sum is σ = 108691072. Its totient is φ = 54263520.

The previous prime is 81456773. The next prime is 81456811. The reversal of 81456789 is 98765418.

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

It is not a de Polignac number, because 81456789 - 2⁴ = 81456773 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81456719) 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, 5272 + ... + 13809.

It is an arithmetic number, because the mean of its divisors is an integer number (13586384).

Almost surely, 2^81456789 is an apocalyptic number.

It is an amenable number.

81456789 is a deficient number, since it is larger than the sum of its proper divisors (27234283).

81456789 is a wasteful number, since it uses less digits than its factorization.

81456789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20507.

The product of its digits is 483840, while the sum is 48.

The square root of 81456789 is about 9025.3414893842. The cubic root of 81456789 is about 433.4866849090.

The spelling of 81456789 in words is "eighty-one million, four hundred fifty-six thousand, seven hundred eighty-nine".