1644366464 has 64 divisors (see below), whose sum is σ = 3576468840. Its totient is φ = 748486656.

The previous prime is 1644366433. The next prime is 1644366467. The reversal of 1644366464 is 4646634461.

It can be written as a sum of positive squares in 4 ways, for example, as 1552360000 + 92006464 = 39400^2 + 9592^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-3 number, since 3×1644366464³ (a number of 29 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (1644366467) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114704 + ... + 128240.

Almost surely, 2^1644366464 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 1644366464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1788234420).

1644366464 is an abundant number, since it is smaller than the sum of its proper divisors (1932102376).

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

1644366464 is a wasteful number, since it uses less digits than its factorization.

1644366464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13637 (or 13625 counting only the distinct ones).

The product of its digits is 995328, while the sum is 44.

The square root of 1644366464 is about 40550.7886976320. The cubic root of 1644366464 is about 1180.3193773056.

The spelling of 1644366464 in words is "one billion, six hundred forty-four million, three hundred sixty-six thousand, four hundred sixty-four".