81245619 has 64 divisors (see below), whose sum is σ = 151782400. Its totient is φ = 41803776.

The previous prime is 81245609. The next prime is 81245663. The reversal of 81245619 is 91654218.

It is not a de Polignac number, because 81245619 - 2⁵ = 81245587 is a prime.

It is a super-2 number, since 2×81245619² = 13201701213386322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81245609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 105267 + ... + 106035.

It is an arithmetic number, because the mean of its divisors is an integer number (2371600).

Almost surely, 2^81245619 is an apocalyptic number.

81245619 is a deficient number, since it is larger than the sum of its proper divisors (70536781).

81245619 is a wasteful number, since it uses less digits than its factorization.

81245619 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 841 (or 835 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 81245619 is about 9013.6351712281. The cubic root of 81245619 is about 433.1117679284. Note that the first 3 decimals are identical.

The spelling of 81245619 in words is "eighty-one million, two hundred forty-five thousand, six hundred nineteen".