9988861920 has 48 divisors (see below), whose sum is σ = 31464916560. Its totient is φ = 2663696384.

The previous prime is 9988861913. The next prime is 9988861931. The reversal of 9988861920 is 291688899.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10404585 + ... + 10405544.

It is an arithmetic number, because the mean of its divisors is an integer number (655519095).

Almost surely, 2^9988861920 is an apocalyptic number.

It is an amenable number.

9988861920 is an abundant number, since it is smaller than the sum of its proper divisors (21476054640).

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

9988861920 is a wasteful number, since it uses less digits than its factorization.

9988861920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20810147 (or 20810139 counting only the distinct ones).

The product of its (nonzero) digits is 4478976, while the sum is 60.

The square root of 9988861920 is about 99944.2940842548. The cubic root of 9988861920 is about 2153.6345173477.

The spelling of 9988861920 in words is "nine billion, nine hundred eighty-eight million, eight hundred sixty-one thousand, nine hundred twenty".