99781281 has 32 divisors (see below), whose sum is σ = 154291200. Its totient is φ = 63659520.

The previous prime is 99781273. The next prime is 99781301. The reversal of 99781281 is 18218799.

It is not a de Polignac number, because 99781281 - 2³ = 99781273 is a prime.

It is a super-2 number, since 2×99781281² = 19912608076001922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (99781261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 80575 + ... + 81803.

It is an arithmetic number, because the mean of its divisors is an integer number (4821600).

Almost surely, 2^99781281 is an apocalyptic number.

It is an amenable number.

99781281 is a deficient number, since it is larger than the sum of its proper divisors (54509919).

99781281 is a wasteful number, since it uses less digits than its factorization.

99781281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1366 (or 1360 counting only the distinct ones).

The product of its digits is 72576, while the sum is 45.

The square root of 99781281 is about 9989.0580637015. The cubic root of 99781281 is about 463.8202351224.

The spelling of 99781281 in words is "ninety-nine million, seven hundred eighty-one thousand, two hundred eighty-one".