81499519 has 8 divisors (see below), whose sum is σ = 82316448. Its totient is φ = 80686080.

The previous prime is 81499499. The next prime is 81499529. The reversal of 81499519 is 91599418.

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 81499519 - 2⁵ = 81499487 is a prime.

It is a super-2 number, since 2×81499519² = 13284343194462722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81499529) 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, 78534 + ... + 79564.

It is an arithmetic number, because the mean of its divisors is an integer number (10289556).

Almost surely, 2^81499519 is an apocalyptic number.

81499519 is a deficient number, since it is larger than the sum of its proper divisors (816929).

81499519 is a wasteful number, since it uses less digits than its factorization.

81499519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1745.

The product of its digits is 116640, while the sum is 46.

The square root of 81499519 is about 9027.7084024685. The cubic root of 81499519 is about 433.5624700721.

The spelling of 81499519 in words is "eighty-one million, four hundred ninety-nine thousand, five hundred nineteen".