81519751 has 8 divisors (see below), whose sum is σ = 85155840. Its totient is φ = 77891352.

The previous prime is 81519733. The next prime is 81519773. The reversal of 81519751 is 15791518.

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

It is a cyclic number.

It is not a de Polignac number, because 81519751 - 2¹³ = 81511559 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81519751.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81519721) 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, 35290 + ... + 37528.

It is an arithmetic number, because the mean of its divisors is an integer number (10644480).

Almost surely, 2^81519751 is an apocalyptic number.

81519751 is a deficient number, since it is larger than the sum of its proper divisors (3636089).

81519751 is a wasteful number, since it uses less digits than its factorization.

81519751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3845.

The product of its digits is 12600, while the sum is 37.

The square root of 81519751 is about 9028.8288830833. The cubic root of 81519751 is about 433.5983439449.

The spelling of 81519751 in words is "eighty-one million, five hundred nineteen thousand, seven hundred fifty-one".