2100866721 has 8 divisors (see below), whose sum is σ = 2813717760. Its totient is φ = 1394296752.

The previous prime is 2100866707. The next prime is 2100866723. The reversal of 2100866721 is 1276680012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2100866721 - 2¹⁷ = 2100735649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2100866723) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 1569486 + ... + 1570823.

It is an arithmetic number, because the mean of its divisors is an integer number (351714720).

Almost surely, 2^2100866721 is an apocalyptic number.

It is an amenable number.

2100866721 is a deficient number, since it is larger than the sum of its proper divisors (712851039).

2100866721 is a wasteful number, since it uses less digits than its factorization.

2100866721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3140535.

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 2100866721 is about 45835.2126754093. The cubic root of 2100866721 is about 1280.7553161295.

The spelling of 2100866721 in words is "two billion, one hundred million, eight hundred sixty-six thousand, seven hundred twenty-one".