2145561100 has 72 divisors (see below), whose sum is σ = 4742696448. Its totient is φ = 842318400.

The previous prime is 2145561091. The next prime is 2145561133. The reversal of 2145561100 is 11655412.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2887329 + ... + 2888071.

It is an arithmetic number, because the mean of its divisors is an integer number (65870784).

Almost surely, 2^2145561100 is an apocalyptic number.

2145561100 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 2145561100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2371348224).

2145561100 is an abundant number, since it is smaller than the sum of its proper divisors (2597135348).

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

2145561100 is a wasteful number, since it uses less digits than its factorization.

2145561100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1255 (or 1248 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 2145561100 is about 46320.2018562096. The cubic root of 2145561100 is about 1289.7740324909.

The spelling of 2145561100 in words is "two billion, one hundred forty-five million, five hundred sixty-one thousand, one hundred".