1636144640 has 160 divisors (see below), whose sum is σ = 4262914656. Its totient is φ = 598671360.

The previous prime is 1636144639. The next prime is 1636144669. The reversal of 1636144640 is 464416361.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (160).

It is a self number, because there is not a number n which added to its sum of digits gives 1636144640.

It is a congruent number.

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, 7021964 + ... + 7022196.

Almost surely, 2^1636144640 is an apocalyptic number.

1636144640 is a gapful number since it is divisible by the number (10) 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 1636144640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2131457328).

1636144640 is an abundant number, since it is smaller than the sum of its proper divisors (2626770016).

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

1636144640 is a wasteful number, since it uses less digits than its factorization.

1636144640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 480 (or 464 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 35.

The square root of 1636144640 is about 40449.2847897216. The cubic root of 1636144640 is about 1178.3488925379.

The spelling of 1636144640 in words is "one billion, six hundred thirty-six million, one hundred forty-four thousand, six hundred forty".