81249518 has 16 divisors (see below), whose sum is σ = 139448544. Its totient is φ = 34780320.

The previous prime is 81249517. The next prime is 81249533. The reversal of 81249518 is 81594218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81249517) 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, 11048 + ... + 16868.

It is an arithmetic number, because the mean of its divisors is an integer number (8715534).

Almost surely, 2^81249518 is an apocalyptic number.

81249518 is a deficient number, since it is larger than the sum of its proper divisors (58199026).

81249518 is a wasteful number, since it uses less digits than its factorization.

81249518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6827.

The product of its digits is 23040, while the sum is 38.

The square root of 81249518 is about 9013.8514520709. The cubic root of 81249518 is about 433.1186962026.

The spelling of 81249518 in words is "eighty-one million, two hundred forty-nine thousand, five hundred eighteen".