3981649920 has 384 divisors, whose sum is σ = 13623966720. Its totient is φ = 990904320.

The previous prime is 3981649913. The next prime is 3981649921. The reversal of 3981649920 is 299461893.

It is a tau number, because it is divible by the number of its divisors (384).

It is not an unprimeable number, because it can be changed into a prime (3981649921) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 35235784 + ... + 35235896.

It is an arithmetic number, because the mean of its divisors is an integer number (35479080).

Almost surely, 2^3981649920 is an apocalyptic number.

3981649920 is a gapful number since it is divisible by the number (30) 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 3981649920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6811983360).

3981649920 is an abundant number, since it is smaller than the sum of its proper divisors (9642316800).

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

3981649920 is a wasteful number, since it uses less digits than its factorization.

3981649920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211 (or 191 counting only the distinct ones).

The product of its (nonzero) digits is 839808, while the sum is 51.

The square root of 3981649920 is about 63100.3163225035. The cubic root of 3981649920 is about 1584.9699191882.

The spelling of 3981649920 in words is "three billion, nine hundred eighty-one million, six hundred forty-nine thousand, nine hundred twenty".