81893745 has 24 divisors (see below), whose sum is σ = 144631656. Its totient is φ = 42851328.

The previous prime is 81893741. The next prime is 81893759. The reversal of 81893745 is 54739818.

It can be written as a sum of positive squares in 4 ways, for example, as 12787776 + 69105969 = 3576^2 + 8313^2 .

It is not a de Polignac number, because 81893745 - 2² = 81893741 is a prime.

It is a super-3 number, since 3×81893745³ (a number of 25 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 81893745.

It is not an unprimeable number, because it can be changed into a prime (81893741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14784 + ... + 19553.

It is an arithmetic number, because the mean of its divisors is an integer number (6026319).

Almost surely, 2^81893745 is an apocalyptic number.

It is an amenable number.

81893745 is a deficient number, since it is larger than the sum of its proper divisors (62737911).

81893745 is a wasteful number, since it uses less digits than its factorization.

81893745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34401 (or 34398 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The square root of 81893745 is about 9049.5162854155. The cubic root of 81893745 is about 434.2604158886.

The spelling of 81893745 in words is "eighty-one million, eight hundred ninety-three thousand, seven hundred forty-five".