3666581640 has 160 divisors (see below), whose sum is σ = 12444569280. Its totient is φ = 968174208.

The previous prime is 3666581629. The next prime is 3666581647. The reversal of 3666581640 is 461856663.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (3666581647) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 328227 + ... + 339213.

It is an arithmetic number, because the mean of its divisors is an integer number (77778558).

Almost surely, 2^3666581640 is an apocalyptic number.

3666581640 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 3666581640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6222284640).

3666581640 is an abundant number, since it is smaller than the sum of its proper divisors (8777987640).

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

3666581640 is a wasteful number, since it uses less digits than its factorization.

3666581640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11113 (or 11100 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The square root of 3666581640 is about 60552.3049932866. The cubic root of 3666581640 is about 1542.0097502752.

The spelling of 3666581640 in words is "three billion, six hundred sixty-six million, five hundred eighty-one thousand, six hundred forty".