3991796640 has 960 divisors, whose sum is σ = 16904764800. Its totient is φ = 877879296.

The previous prime is 3991796603. The next prime is 3991796647. The reversal of 3991796640 is 466971993.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (3991796647) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 92832459 + ... + 92832501.

It is an arithmetic number, because the mean of its divisors is an integer number (17609130).

Almost surely, 2^3991796640 is an apocalyptic number.

3991796640 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 3991796640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8452382400).

3991796640 is an abundant number, since it is smaller than the sum of its proper divisors (12912968160).

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

3991796640 is a wasteful number, since it uses less digits than its factorization.

3991796640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131 (or 114 counting only the distinct ones).

The product of its (nonzero) digits is 2204496, while the sum is 54.

The square root of 3991796640 is about 63180.6666631494. Note that the first 5 decimals coincide. The cubic root of 3991796640 is about 1586.3151407617.

The spelling of 3991796640 in words is "three billion, nine hundred ninety-one million, seven hundred ninety-six thousand, six hundred forty".