3991339680 has 96 divisors (see below), whose sum is σ = 12690385344. Its totient is φ = 1054396416.

The previous prime is 3991339619. The next prime is 3991339697. The reversal of 3991339680 is 869331993.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×3991339680² = 31861584882285004800, which contains 22 as substring.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12504 + ... + 90216.

It is an arithmetic number, because the mean of its divisors is an integer number (132191514).

Almost surely, 2^3991339680 is an apocalyptic number.

3991339680 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 3991339680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6345192672).

3991339680 is an abundant number, since it is smaller than the sum of its proper divisors (8699045664).

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

3991339680 is a wasteful number, since it uses less digits than its factorization.

3991339680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77838 (or 77830 counting only the distinct ones).

The product of its (nonzero) digits is 944784, while the sum is 51.

The square root of 3991339680 is about 63177.0502635253. The cubic root of 3991339680 is about 1586.2546074318.

The spelling of 3991339680 in words is "three billion, nine hundred ninety-one million, three hundred thirty-nine thousand, six hundred eighty".