99381971808 has 144 divisors (see below), whose sum is σ = 337034670336. Its totient is φ = 27160277760.

The previous prime is 99381971803. The next prime is 99381971809. The reversal of 99381971808 is 80817918399.

99381971808 is a `hidden beast` number, since 99 + 381 + 97 + 1 + 80 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×99381971808² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99381971803) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1025298 + ... + 1118033.

It is an arithmetic number, because the mean of its divisors is an integer number (2340518544).

Almost surely, 2^99381971808 is an apocalyptic number.

It is an amenable number.

99381971808 is an abundant number, since it is smaller than the sum of its proper divisors (237652698528).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

99381971808 is a wasteful number, since it uses less digits than its factorization.

99381971808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2143377 (or 2143366 counting only the distinct ones).

The product of its (nonzero) digits is 7838208, while the sum is 63.

The spelling of 99381971808 in words is "ninety-nine billion, three hundred eighty-one million, nine hundred seventy-one thousand, eight hundred eight".