1644963380 has 24 divisors (see below), whose sum is σ = 3636235680. Its totient is φ = 623354400.

The previous prime is 1644963379. The next prime is 1644963443. The reversal of 1644963380 is 833694461.

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 in 7 ways as a sum of consecutive naturals, for example, 2164046 + ... + 2164805.

It is an arithmetic number, because the mean of its divisors is an integer number (151509820).

Almost surely, 2^1644963380 is an apocalyptic number.

1644963380 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1644963380 is an abundant number, since it is smaller than the sum of its proper divisors (1991272300).

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

1644963380 is a wasteful number, since it uses less digits than its factorization.

1644963380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4328879 (or 4328877 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 44.

The square root of 1644963380 is about 40558.1481332666. The cubic root of 1644963380 is about 1180.4621812976.

The spelling of 1644963380 in words is "one billion, six hundred forty-four million, nine hundred sixty-three thousand, three hundred eighty".