2156664202685 has 4 divisors (see below), whose sum is σ = 2587997043228. Its totient is φ = 1725331362144.

The previous prime is 2156664202681. The next prime is 2156664202687. The reversal of 2156664202685 is 5862024666512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1608772603876 + 547891598809 = 1268374^2 + 740197^2 .

It is a cyclic number.

It is not a de Polignac number, because 2156664202685 - 2² = 2156664202681 is a prime.

It is a super-2 number, since 2×2156664202685² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2156664202681) 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, 215666420264 + ... + 215666420273.

It is an arithmetic number, because the mean of its divisors is an integer number (646999260807).

Almost surely, 2^{2156664202685} is an apocalyptic number.

It is an amenable number.

2156664202685 is a deficient number, since it is larger than the sum of its proper divisors (431332840543).

2156664202685 is an equidigital number, since it uses as much as digits as its factorization.

2156664202685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431332840542.

The product of its (nonzero) digits is 8294400, while the sum is 53.

The spelling of 2156664202685 in words is "two trillion, one hundred fifty-six billion, six hundred sixty-four million, two hundred two thousand, six hundred eighty-five".