2156561212 has 48 divisors (see below), whose sum is σ = 4104051840. Its totient is φ = 985652928.

The previous prime is 2156561203. The next prime is 2156561257. The reversal of 2156561212 is 2121656512.

It is a super-3 number, since 3×2156561212³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 4123183 + ... + 4123705.

It is an arithmetic number, because the mean of its divisors is an integer number (85501080).

Almost surely, 2^2156561212 is an apocalyptic number.

It is an amenable number.

2156561212 is a deficient number, since it is larger than the sum of its proper divisors (1947490628).

2156561212 is a wasteful number, since it uses less digits than its factorization.

2156561212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1162 (or 1160 counting only the distinct ones).

The product of its digits is 7200, while the sum is 31.

The square root of 2156561212 is about 46438.7899497823. The cubic root of 2156561212 is about 1291.9744640897.

The spelling of 2156561212 in words is "two billion, one hundred fifty-six million, five hundred sixty-one thousand, two hundred twelve".