2156606921 has 16 divisors (see below), whose sum is σ = 2523679104. Its totient is φ = 1804771584.

The previous prime is 2156606911. The next prime is 2156606957. The reversal of 2156606921 is 1296066512.

It is a de Polignac number, because none of the positive numbers 2^k-2156606921 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2156606911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32651 + ... + 73343.

It is an arithmetic number, because the mean of its divisors is an integer number (157729944).

Almost surely, 2^2156606921 is an apocalyptic number.

It is an amenable number.

2156606921 is a deficient number, since it is larger than the sum of its proper divisors (367072183).

2156606921 is a wasteful number, since it uses less digits than its factorization.

2156606921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40880.

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 2156606921 is about 46439.2820896275. The cubic root of 2156606921 is about 1291.9835919616.

The spelling of 2156606921 in words is "two billion, one hundred fifty-six million, six hundred six thousand, nine hundred twenty-one".