1644644374 has 4 divisors (see below), whose sum is σ = 2466966564. Its totient is φ = 822322186.

The previous prime is 1644644369. The next prime is 1644644383. The reversal of 1644644374 is 4734464461.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1644644374.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411161092 + ... + 411161095.

It is an arithmetic number, because the mean of its divisors is an integer number (616741641).

Almost surely, 2^1644644374 is an apocalyptic number.

1644644374 is a deficient number, since it is larger than the sum of its proper divisors (822322190).

1644644374 is an equidigital number, since it uses as much as digits as its factorization.

1644644374 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 822322189.

The product of its digits is 774144, while the sum is 43.

The square root of 1644644374 is about 40554.2152433012. The cubic root of 1644644374 is about 1180.3858677722.

The spelling of 1644644374 in words is "one billion, six hundred forty-four million, six hundred forty-four thousand, three hundred seventy-four".