2116501681 has 4 divisors (see below), whose sum is σ = 2418859072. Its totient is φ = 1814144292.

The previous prime is 2116501663. The next prime is 2116501687. The reversal of 2116501681 is 1861056112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2116501681 - 2⁷ = 2116501553 is a prime.

It is a super-2 number, since 2×2116501681² = 8959158731351651522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2116501687) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 151178685 + ... + 151178698.

It is an arithmetic number, because the mean of its divisors is an integer number (604714768).

Almost surely, 2^2116501681 is an apocalyptic number.

It is an amenable number.

2116501681 is a deficient number, since it is larger than the sum of its proper divisors (302357391).

2116501681 is an equidigital number, since it uses as much as digits as its factorization.

2116501681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 302357390.

The product of its (nonzero) digits is 2880, while the sum is 31.

The square root of 2116501681 is about 46005.4527311709. The cubic root of 2116501681 is about 1283.9246568385.

Adding to 2116501681 its reverse (1861056112), we get a palindrome (3977557793).

The spelling of 2116501681 in words is "two billion, one hundred sixteen million, five hundred one thousand, six hundred eighty-one".