1645951944 has 384 divisors, whose sum is σ = 5589319680. Its totient is φ = 399168000.

The previous prime is 1645951933. The next prime is 1645951963. The reversal of 1645951944 is 4491595461.

It is a junction number, because it is equal to n+sod(n) for n = 1645951893 and 1645951902.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 10900269 + ... + 10900419.

It is an arithmetic number, because the mean of its divisors is an integer number (14555520).

Almost surely, 2^1645951944 is an apocalyptic number.

1645951944 is a gapful number since it is divisible by the number (14) 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 1645951944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2794659840).

1645951944 is an abundant number, since it is smaller than the sum of its proper divisors (3943367736).

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

1645951944 is a wasteful number, since it uses less digits than its factorization.

1645951944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241 (or 230 counting only the distinct ones).

The product of its digits is 777600, while the sum is 48.

The square root of 1645951944 is about 40570.3332990992. Note that the first 3 decimals coincide. The cubic root of 1645951944 is about 1180.6986057555.

The spelling of 1645951944 in words is "one billion, six hundred forty-five million, nine hundred fifty-one thousand, nine hundred forty-four".