9861621120 has 768 divisors, whose sum is σ = 39777454080. Its totient is φ = 2229534720.

The previous prime is 9861621101. The next prime is 9861621127. The reversal of 9861621120 is 211261689.

9861621120 is a `hidden beast` number, since 9 + 8 + 6 + 1 + 621 + 1 + 20 = 666.

It is a super-2 number, since 2×9861621120² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9861621127) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 77650497 + ... + 77650623.

It is an arithmetic number, because the mean of its divisors is an integer number (51793560).

Almost surely, 2^9861621120 is an apocalyptic number.

9861621120 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 9861621120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19888727040).

9861621120 is an abundant number, since it is smaller than the sum of its proper divisors (29915832960).

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

9861621120 is a wasteful number, since it uses less digits than its factorization.

9861621120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243 (or 228 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 9861621120 is about 99305.6953049522. The cubic root of 9861621120 is about 2144.4508872011.

The spelling of 9861621120 in words is "nine billion, eight hundred sixty-one million, six hundred twenty-one thousand, one hundred twenty".