99981655 has 4 divisors (see below), whose sum is σ = 119977992. Its totient is φ = 79985320.

The previous prime is 99981653. The next prime is 99981697. The reversal of 99981655 is 55618999.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55618999 = 2239 ⋅24841.

It is not a de Polignac number, because 99981655 - 2¹ = 99981653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99981653) 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 3 ways as a sum of consecutive naturals, for example, 9998161 + ... + 9998170.

It is an arithmetic number, because the mean of its divisors is an integer number (29994498).

Almost surely, 2^99981655 is an apocalyptic number.

99981655 is a deficient number, since it is larger than the sum of its proper divisors (19996337).

99981655 is a wasteful number, since it uses less digits than its factorization.

99981655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19996336.

The product of its digits is 874800, while the sum is 52.

The square root of 99981655 is about 9999.0827079288. The cubic root of 99981655 is about 464.1304983097.

The spelling of 99981655 in words is "ninety-nine million, nine hundred eighty-one thousand, six hundred fifty-five".