3721405644 has 144 divisors (see below), whose sum is σ = 10512343296. Its totient is φ = 1100534400.

The previous prime is 3721405643. The next prime is 3721405691. The reversal of 3721405644 is 4465041273.

3721405644 is a `hidden beast` number, since 3 + 7 + 2 + 1 + 4 + 0 + 5 + 644 = 666.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 3721405599 and 3721405608.

It is not an unprimeable number, because it can be changed into a prime (3721405643) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3007794 + ... + 3009030.

It is an arithmetic number, because the mean of its divisors is an integer number (73002384).

Almost surely, 2^3721405644 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 3721405644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5256171648).

3721405644 is an abundant number, since it is smaller than the sum of its proper divisors (6790937652).

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

3721405644 is a wasteful number, since it uses less digits than its factorization.

3721405644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1436 (or 1431 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 36.

The square root of 3721405644 is about 61003.3248602074. The cubic root of 3721405644 is about 1549.6573150159.

The spelling of 3721405644 in words is "three billion, seven hundred twenty-one million, four hundred five thousand, six hundred forty-four".