81948759 has 8 divisors (see below), whose sum is σ = 111326832. Its totient is φ = 53601600.

The previous prime is 81948749. The next prime is 81948781. The reversal of 81948759 is 95784918.

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

It is not a de Polignac number, because 81948759 - 2⁷ = 81948631 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81948749) 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 7 ways as a sum of consecutive naturals, for example, 257542 + ... + 257859.

It is an arithmetic number, because the mean of its divisors is an integer number (13915854).

Almost surely, 2^81948759 is an apocalyptic number.

81948759 is a deficient number, since it is larger than the sum of its proper divisors (29378073).

81948759 is a wasteful number, since it uses less digits than its factorization.

81948759 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 515457.

The product of its digits is 725760, while the sum is 51.

The square root of 81948759 is about 9052.5553850833. Note that the first 3 decimals coincide. The cubic root of 81948759 is about 434.3576355842.

The spelling of 81948759 in words is "eighty-one million, nine hundred forty-eight thousand, seven hundred fifty-nine".