2161220136 has 32 divisors (see below), whose sum is σ = 5404299360. Its totient is φ = 720240192.

The previous prime is 2161220123. The next prime is 2161220161. The reversal of 2161220136 is 6310221612.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 139851 + ... + 154533.

It is an arithmetic number, because the mean of its divisors is an integer number (168884355).

Almost surely, 2^2161220136 is an apocalyptic number.

It is an amenable number.

2161220136 is an abundant number, since it is smaller than the sum of its proper divisors (3243079224).

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

2161220136 is a wasteful number, since it uses less digits than its factorization.

2161220136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20825 (or 20821 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 2161220136 is about 46488.9248746408. The cubic root of 2161220136 is about 1292.9041666594.

Adding to 2161220136 its reverse (6310221612), we get a palindrome (8471441748).

The spelling of 2161220136 in words is "two billion, one hundred sixty-one million, two hundred twenty thousand, one hundred thirty-six".