99981641 has 8 divisors (see below), whose sum is σ = 106638120. Its totient is φ = 93411328.

The previous prime is 99981631. The next prime is 99981649. The reversal of 99981641 is 14618999.

It can be written as a sum of positive squares in 4 ways, for example, as 4020025 + 95961616 = 2005^2 + 9796^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-99981641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99981649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19136 + ... + 23793.

It is an arithmetic number, because the mean of its divisors is an integer number (13329765).

Almost surely, 2^99981641 is an apocalyptic number.

It is an amenable number.

99981641 is a deficient number, since it is larger than the sum of its proper divisors (6656479).

99981641 is a wasteful number, since it uses less digits than its factorization.

99981641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43083.

The product of its digits is 139968, while the sum is 47.

The square root of 99981641 is about 9999.0820078645. The cubic root of 99981641 is about 464.1304766463.

The spelling of 99981641 in words is "ninety-nine million, nine hundred eighty-one thousand, six hundred forty-one".