2153776661 has 4 divisors (see below), whose sum is σ = 2156563692. Its totient is φ = 2150989632.

The previous prime is 2153776657. The next prime is 2153776663. The reversal of 2153776661 is 1666773512.

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 976875025 + 1176901636 = 31255^2 + 34306^2 .

It is a cyclic number.

It is not a de Polignac number, because 2153776661 - 2² = 2153776657 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2153776663) 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, 1392356 + ... + 1393901.

It is an arithmetic number, because the mean of its divisors is an integer number (539140923).

Almost surely, 2^2153776661 is an apocalyptic number.

It is an amenable number.

2153776661 is a deficient number, since it is larger than the sum of its proper divisors (2787031).

2153776661 is an equidigital number, since it uses as much as digits as its factorization.

2153776661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2787030.

The product of its digits is 317520, while the sum is 44.

The square root of 2153776661 is about 46408.7993919257. The cubic root of 2153776661 is about 1291.4181589451.

The spelling of 2153776661 in words is "two billion, one hundred fifty-three million, seven hundred seventy-six thousand, six hundred sixty-one".