2157441664 has 64 divisors (see below), whose sum is σ = 4919745600. Its totient is φ = 923166720.

The previous prime is 2157441647. The next prime is 2157441667. The reversal of 2157441664 is 4661447512.

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (2157441667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 725172 + ... + 728140.

It is an arithmetic number, because the mean of its divisors is an integer number (76871025).

Almost surely, 2^2157441664 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 2157441664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2459872800).

2157441664 is an abundant number, since it is smaller than the sum of its proper divisors (2762303936).

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

2157441664 is an equidigital number, since it uses as much as digits as its factorization.

2157441664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3801 (or 3789 counting only the distinct ones).

The product of its digits is 161280, while the sum is 40.

The square root of 2157441664 is about 46448.2686867875. The cubic root of 2157441664 is about 1292.1502635253.

The spelling of 2157441664 in words is "two billion, one hundred fifty-seven million, four hundred forty-one thousand, six hundred sixty-four".