2165123400 has 384 divisors, whose sum is σ = 8099481600. Its totient is φ = 471961600.

The previous prime is 2165123399. The next prime is 2165123419. The reversal of 2165123400 is 43215612.

It is a Harshad number since it is a multiple of its sum of digits (24).

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, 2580181 + ... + 2581019.

It is an arithmetic number, because the mean of its divisors is an integer number (21092400).

Almost surely, 2^2165123400 is an apocalyptic number.

2165123400 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 2165123400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4049740800).

2165123400 is an abundant number, since it is smaller than the sum of its proper divisors (5934358200).

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

2165123400 is a wasteful number, since it uses less digits than its factorization.

2165123400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 909 (or 900 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 2165123400 is about 46530.8865163775. The cubic root of 2165123400 is about 1293.6820468871.

It can be divided in two parts, 216512 and 3400, that added together give a palindrome (219912).

The spelling of 2165123400 in words is "two billion, one hundred sixty-five million, one hundred twenty-three thousand, four hundred".