9901890540 has 144 divisors (see below), whose sum is σ = 31406671296. Its totient is φ = 2520460800.

The previous prime is 9901890521. The next prime is 9901890547. The reversal of 9901890540 is 450981099.

9901890540 is a `hidden beast` number, since 9 + 9 + 0 + 18 + 90 + 540 = 666.

It is a super-2 number, since 2×9901890540² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (9901890547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2237530 + ... + 2241950.

It is an arithmetic number, because the mean of its divisors is an integer number (218101884).

Almost surely, 2^9901890540 is an apocalyptic number.

9901890540 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9901890540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15703335648).

9901890540 is an abundant number, since it is smaller than the sum of its proper divisors (21504780756).

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

9901890540 is a wasteful number, since it uses less digits than its factorization.

9901890540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5000 (or 4995 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 45.

The square root of 9901890540 is about 99508.2435781076. The cubic root of 9901890540 is about 2147.3658412162.

The spelling of 9901890540 in words is "nine billion, nine hundred one million, eight hundred ninety thousand, five hundred forty".