9861865920 has 336 divisors, whose sum is σ = 36434743488. Its totient is φ = 2439413760.

The previous prime is 9861865859. The next prime is 9861865927. The reversal of 9861865920 is 295681689.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9861865927) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3474742 + ... + 3477578.

Almost surely, 2^9861865920 is an apocalyptic number.

9861865920 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 9861865920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18217371744).

9861865920 is an abundant number, since it is smaller than the sum of its proper divisors (26572877568).

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

9861865920 is a wasteful number, since it uses less digits than its factorization.

9861865920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2948 (or 2935 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 54.

The square root of 9861865920 is about 99306.9278550092. The cubic root of 9861865920 is about 2144.4686313166.

The spelling of 9861865920 in words is "nine billion, eight hundred sixty-one million, eight hundred sixty-five thousand, nine hundred twenty".