1649940864 has 128 divisors (see below), whose sum is σ = 5149025280. Its totient is φ = 461506560.

The previous prime is 1649940823. The next prime is 1649940881. The reversal of 1649940864 is 4680499461.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39889 + ... + 69935.

It is an arithmetic number, because the mean of its divisors is an integer number (40226760).

Almost surely, 2^1649940864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1649940864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2574512640).

1649940864 is an abundant number, since it is smaller than the sum of its proper divisors (3499084416).

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

1649940864 is a wasteful number, since it uses less digits than its factorization.

1649940864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30088 (or 30076 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 51.

The square root of 1649940864 is about 40619.4641028165. The cubic root of 1649940864 is about 1181.6516333320.

The spelling of 1649940864 in words is "one billion, six hundred forty-nine million, nine hundred forty thousand, eight hundred sixty-four".