3721691808 has 72 divisors (see below), whose sum is σ = 10598092596. Its totient is φ = 1238860800.

The previous prime is 3721691797. The next prime is 3721691821. The reversal of 3721691808 is 8081961273.

It can be written as a sum of positive squares in 2 ways, for example, as 3714658704 + 7033104 = 60948^2 + 2652^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 210678 + ... + 227658.

Almost surely, 2^3721691808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 3721691808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5299046298).

3721691808 is an abundant number, since it is smaller than the sum of its proper divisors (6876400788).

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

3721691808 is a wasteful number, since it uses less digits than its factorization.

3721691808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17758 (or 17747 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 3721691808 is about 61005.6702938342. The cubic root of 3721691808 is about 1549.6970352015.

The spelling of 3721691808 in words is "three billion, seven hundred twenty-one million, six hundred ninety-one thousand, eight hundred eight".