2155210640 has 80 divisors (see below), whose sum is σ = 5490987840. Its totient is φ = 780188160.

The previous prime is 2155210601. The next prime is 2155210691. The reversal of 2155210640 is 460125512.

It is a tau number, because it is divible by the number of its divisors (80).

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, 194366 + ... + 205154.

It is an arithmetic number, because the mean of its divisors is an integer number (68637348).

Almost surely, 2^2155210640 is an apocalyptic number.

2155210640 is a gapful number since it is divisible by the number (20) 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 2155210640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2745493920).

2155210640 is an abundant number, since it is smaller than the sum of its proper divisors (3335777200).

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

2155210640 is a wasteful number, since it uses less digits than its factorization.

2155210640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11040 (or 11034 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 2155210640 is about 46424.2462512855. The cubic root of 2155210640 is about 1291.7047029983.

The spelling of 2155210640 in words is "two billion, one hundred fifty-five million, two hundred ten thousand, six hundred forty".