3721645440 has 640 divisors, whose sum is σ = 14555661120. Its totient is φ = 902430720.

The previous prime is 3721645427. The next prime is 3721645453. The reversal of 3721645440 is 445461273.

3721645440 is a `hidden beast` number, since 3 + 7 + 2 + 1 + 645 + 4 + 4 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (3721645427) and next prime (3721645453).

It is a tau number, because it is divible by the number of its divisors (640).

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 = 3721645395 and 3721645404.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 36132429 + ... + 36132531.

Almost surely, 2^3721645440 is an apocalyptic number.

3721645440 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 3721645440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7277830560).

3721645440 is an abundant number, since it is smaller than the sum of its proper divisors (10834015680).

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

3721645440 is a wasteful number, since it uses less digits than its factorization.

3721645440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 171 counting only the distinct ones).

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

The square root of 3721645440 is about 61005.2902624027. The cubic root of 3721645440 is about 1549.6905993605.

The spelling of 3721645440 in words is "three billion, seven hundred twenty-one million, six hundred forty-five thousand, four hundred forty".