1644651970 has 64 divisors (see below), whose sum is σ = 3368252160. Its totient is φ = 573177600.

The previous prime is 1644651937. The next prime is 1644651977. The reversal of 1644651970 is 791564461.

It is not an unprimeable number, because it can be changed into a prime (1644651977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 767100 + ... + 769240.

It is an arithmetic number, because the mean of its divisors is an integer number (52628940).

Almost surely, 2^1644651970 is an apocalyptic number.

1644651970 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1644651970 is an abundant number, since it is smaller than the sum of its proper divisors (1723600190).

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

1644651970 is a wasteful number, since it uses less digits than its factorization.

1644651970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2491.

The product of its (nonzero) digits is 181440, while the sum is 43.

The square root of 1644651970 is about 40554.3088956032. The cubic root of 1644651970 is about 1180.3876850237.

The spelling of 1644651970 in words is "one billion, six hundred forty-four million, six hundred fifty-one thousand, nine hundred seventy".