2161781272 has 16 divisors (see below), whose sum is σ = 4632388560. Its totient is φ = 926477664.

The previous prime is 2161781267. The next prime is 2161781317. The reversal of 2161781272 is 2721871612.

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 3 ways as a sum of consecutive naturals, for example, 19301563 + ... + 19301674.

It is an arithmetic number, because the mean of its divisors is an integer number (289524285).

Almost surely, 2^2161781272 is an apocalyptic number.

It is an amenable number.

2161781272 is an abundant number, since it is smaller than the sum of its proper divisors (2470607288).

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

2161781272 is a wasteful number, since it uses less digits than its factorization.

2161781272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38603250 (or 38603246 counting only the distinct ones).

The product of its digits is 18816, while the sum is 37.

The square root of 2161781272 is about 46494.9596408041. The cubic root of 2161781272 is about 1293.0160528852.

The spelling of 2161781272 in words is "two billion, one hundred sixty-one million, seven hundred eighty-one thousand, two hundred seventy-two".