1644391936 has 160 divisors (see below), whose sum is σ = 3834040320. Its totient is φ = 702535680.

The previous prime is 1644391927. The next prime is 1644391951. The reversal of 1644391936 is 6391934461.

It is a super-3 number, since 3×1644391936³ (a number of 29 digits) contains 333 as substring.

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, 12947905 + ... + 12948031.

It is an arithmetic number, because the mean of its divisors is an integer number (23962752).

Almost surely, 2^1644391936 is an apocalyptic number.

1644391936 is a gapful number since it is divisible by the number (16) 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 1644391936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1917020160).

1644391936 is an abundant number, since it is smaller than the sum of its proper divisors (2189648384).

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

1644391936 is an equidigital number, since it uses as much as digits as its factorization.

1644391936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197 (or 159 counting only the distinct ones).

The product of its digits is 419904, while the sum is 46.

The square root of 1644391936 is about 40551.1027716880. The cubic root of 1644391936 is about 1180.3254718392.

It can be divided in two parts, 164439 and 1936, that added together give a cube (166375 = 55³).

The spelling of 1644391936 in words is "one billion, six hundred forty-four million, three hundred ninety-one thousand, nine hundred thirty-six".