1644263712 has 240 divisors, whose sum is σ = 5952526272. Its totient is φ = 433589760.

The previous prime is 1644263701. The next prime is 1644263741. The reversal of 1644263712 is 2173624461.

1644263712 is a `hidden beast` number, since 1 + 6 + 4 + 4 + 2 + 637 + 12 = 666.

It is a super-3 number, since 3×1644263712³ (a number of 29 digits) contains 333 as substring.

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

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 232387 + ... + 239357.

Almost surely, 2^1644263712 is an apocalyptic number.

1644263712 is a gapful number since it is divisible by the number (12) 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 1644263712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2976263136).

1644263712 is an abundant number, since it is smaller than the sum of its proper divisors (4308262560).

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

1644263712 is a wasteful number, since it uses less digits than its factorization.

1644263712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7013 (or 6996 counting only the distinct ones).

The product of its digits is 48384, while the sum is 36.

The square root of 1644263712 is about 40549.5217234433. The cubic root of 1644263712 is about 1180.2947918080.

It can be divided in two parts, 1644 and 263712, that added together give a triangular number (265356 = T₇₂₈).

The spelling of 1644263712 in words is "one billion, six hundred forty-four million, two hundred sixty-three thousand, seven hundred twelve".