81225519 has 16 divisors (see below), whose sum is σ = 110170368. Its totient is φ = 53223872.

The previous prime is 81225511. The next prime is 81225523. The reversal of 81225519 is 91552218.

It is a cyclic number.

It is not a de Polignac number, because 81225519 - 2³ = 81225511 is a prime.

It is a super-2 number, since 2×81225519² = 13195169873638722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81225519.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81225511) 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 15 ways as a sum of consecutive naturals, for example, 43054 + ... + 44900.

It is an arithmetic number, because the mean of its divisors is an integer number (6885648).

Almost surely, 2^81225519 is an apocalyptic number.

81225519 is a deficient number, since it is larger than the sum of its proper divisors (28944849).

81225519 is a wasteful number, since it uses less digits than its factorization.

81225519 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2094.

The product of its digits is 7200, while the sum is 33.

The square root of 81225519 is about 9012.5201248042. The cubic root of 81225519 is about 433.0760479940.

The spelling of 81225519 in words is "eighty-one million, two hundred twenty-five thousand, five hundred nineteen".