3961681920 has 768 divisors, whose sum is σ = 16982784000. Its totient is φ = 856424448.

The previous prime is 3961681907. The next prime is 3961681931. The reversal of 3961681920 is 291861693.

It is a happy number.

3961681920 is a `hidden beast` number, since 3 + 9 + 616 + 8 + 1 + 9 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (768).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 44513236 + ... + 44513324.

It is an arithmetic number, because the mean of its divisors is an integer number (22113000).

Almost surely, 2^3961681920 is an apocalyptic number.

3961681920 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 3961681920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8491392000).

3961681920 is an abundant number, since it is smaller than the sum of its proper divisors (13021102080).

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

3961681920 is a wasteful number, since it uses less digits than its factorization.

3961681920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155 (or 129 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 3961681920 is about 62941.8932031759. The cubic root of 3961681920 is about 1582.3159328600.

The spelling of 3961681920 in words is "three billion, nine hundred sixty-one million, six hundred eighty-one thousand, nine hundred twenty".