9923890081 has 12 divisors (see below), whose sum is σ = 11553229908. Its totient is φ = 8499476832.

The previous prime is 9923890079. The next prime is 9923890111. The reversal of 9923890081 is 1800983299.

It can be written as a sum of positive squares in 2 ways, for example, as 2273763856 + 7650126225 = 47684^2 + 87465^2 .

It is not a de Polignac number, because 9923890081 - 2¹ = 9923890079 is a prime.

It is a super-2 number, since 2×9923890081² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9923890001) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16726 + ... + 141871.

It is an arithmetic number, because the mean of its divisors is an integer number (962769159).

Almost surely, 2^9923890081 is an apocalyptic number.

It is an amenable number.

9923890081 is a deficient number, since it is larger than the sum of its proper divisors (1629339827).

9923890081 is a wasteful number, since it uses less digits than its factorization.

9923890081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159888 (or 159881 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 49.

The square root of 9923890081 is about 99618.7235463294. The cubic root of 9923890081 is about 2148.9549694009.

The spelling of 9923890081 in words is "nine billion, nine hundred twenty-three million, eight hundred ninety thousand, eighty-one".