2053720661 has 4 divisors (see below), whose sum is σ = 2055679500. Its totient is φ = 2051761824.

The previous prime is 2053720651. The next prime is 2053720673. The reversal of 2053720661 is 1660273502.

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 1297800625 + 755920036 = 36025^2 + 27494^2 .

It is a cyclic number.

It is not a de Polignac number, because 2053720661 - 2¹⁰ = 2053719637 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2053720651) 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, 977846 + ... + 979943.

It is an arithmetic number, because the mean of its divisors is an integer number (513919875).

Almost surely, 2^2053720661 is an apocalyptic number.

It is an amenable number.

2053720661 is a deficient number, since it is larger than the sum of its proper divisors (1958839).

2053720661 is a wasteful number, since it uses less digits than its factorization.

2053720661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1958838.

The product of its (nonzero) digits is 15120, while the sum is 32.

The square root of 2053720661 is about 45317.9948916542. The cubic root of 2053720661 is about 1271.1021620314.

The spelling of 2053720661 in words is "two billion, fifty-three million, seven hundred twenty thousand, six hundred sixty-one".