81469815 has 64 divisors (see below), whose sum is σ = 158807040. Its totient is φ = 34836480.

The previous prime is 81469811. The next prime is 81469837. The reversal of 81469815 is 51896418.

It is not a de Polignac number, because 81469815 - 2² = 81469811 is a prime.

It is a super-2 number, since 2×81469815² = 13274661512268450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81469811) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 193305 + ... + 193725.

It is an arithmetic number, because the mean of its divisors is an integer number (2481360).

Almost surely, 2^81469815 is an apocalyptic number.

81469815 is a deficient number, since it is larger than the sum of its proper divisors (77337225).

81469815 is a wasteful number, since it uses less digits than its factorization.

81469815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 552.

The product of its digits is 69120, while the sum is 42.

The square root of 81469815 is about 9026.0630952814. The cubic root of 81469815 is about 433.5097903971.

The spelling of 81469815 in words is "eighty-one million, four hundred sixty-nine thousand, eight hundred fifteen".