81500519 has 8 divisors (see below), whose sum is σ = 88558080. Its totient is φ = 74719800.

The previous prime is 81500513. The next prime is 81500521. The reversal of 81500519 is 91500518.

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 81500519 - 2¹² = 81496423 is a prime.

It is a super-2 number, since 2×81500519² = 13284669194538722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81500491 and 81500500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81500513) 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, 68597 + ... + 69774.

It is an arithmetic number, because the mean of its divisors is an integer number (11069760).

Almost surely, 2^81500519 is an apocalyptic number.

81500519 is a deficient number, since it is larger than the sum of its proper divisors (7057561).

81500519 is a wasteful number, since it uses less digits than its factorization.

81500519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138421.

The product of its (nonzero) digits is 1800, while the sum is 29.

The square root of 81500519 is about 9027.7637873396. The cubic root of 81500519 is about 433.5642433370.

Subtracting 81500519 from its reverse (91500518), we obtain a palindrome (9999999).

The spelling of 81500519 in words is "eighty-one million, five hundred thousand, five hundred nineteen".