1644581416 has 32 divisors (see below), whose sum is σ = 3195369000. Its totient is φ = 792580096.

The previous prime is 1644581369. The next prime is 1644581447. The reversal of 1644581416 is 6141854461.

It can be written as a sum of positive squares in 4 ways, for example, as 742780516 + 901800900 = 27254^2 + 30030^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 137400 + ... + 148888.

Almost surely, 2^1644581416 is an apocalyptic number.

It is an amenable number.

1644581416 is a deficient number, since it is larger than the sum of its proper divisors (1550787584).

1644581416 is a wasteful number, since it uses less digits than its factorization.

1644581416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12141 (or 12137 counting only the distinct ones).

The product of its digits is 92160, while the sum is 40.

The square root of 1644581416 is about 40553.4390156988. The cubic root of 1644581416 is about 1180.3708056139.

The spelling of 1644581416 in words is "one billion, six hundred forty-four million, five hundred eighty-one thousand, four hundred sixteen".