81000447 has 16 divisors (see below), whose sum is σ = 119242368. Its totient is φ = 48498080.

The previous prime is 81000431. The next prime is 81000449. The reversal of 81000447 is 74400018.

It is a cyclic number.

It is not a de Polignac number, because 81000447 - 2⁴ = 81000431 is a prime.

It is a super-2 number, since 2×81000447² = 13122144828399618, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81000449) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12048 + ... + 17525.

It is an arithmetic number, because the mean of its divisors is an integer number (7452648).

Almost surely, 2^81000447 is an apocalyptic number.

81000447 is a deficient number, since it is larger than the sum of its proper divisors (38241921).

81000447 is a wasteful number, since it uses less digits than its factorization.

81000447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29670.

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 81000447 is about 9000.0248332991. The cubic root of 81000447 is about 432.6756669989.

The spelling of 81000447 in words is "eighty-one million, four hundred forty-seven", and thus it is an aban number.