2135216681 has 8 divisors (see below), whose sum is σ = 2299840200. Its totient is φ = 1970646912.

The previous prime is 2135216663. The next prime is 2135216687. The reversal of 2135216681 is 1866125312.

It can be written as a sum of positive squares in 4 ways, for example, as 1360429456 + 774787225 = 36884^2 + 27835^2 .

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

It is not a de Polignac number, because 2135216681 - 2⁶ = 2135216617 is a prime.

It is a super-2 number, since 2×2135216681² = 9118300549641311522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2135216687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 113645 + ... + 131093.

It is an arithmetic number, because the mean of its divisors is an integer number (287480025).

Almost surely, 2^2135216681 is an apocalyptic number.

It is an amenable number.

2135216681 is a deficient number, since it is larger than the sum of its proper divisors (164623519).

2135216681 is a wasteful number, since it uses less digits than its factorization.

2135216681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26875.

The product of its digits is 17280, while the sum is 35.

The square root of 2135216681 is about 46208.4048740053. The cubic root of 2135216681 is about 1287.6978914221.

The spelling of 2135216681 in words is "two billion, one hundred thirty-five million, two hundred sixteen thousand, six hundred eighty-one".