2443257661 has 4 divisors (see below), whose sum is σ = 2631200572. Its totient is φ = 2255314752.

The previous prime is 2443257643. The next prime is 2443257701. The reversal of 2443257661 is 1667523442.

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 326705625 + 2116552036 = 18075^2 + 46006^2 .

It is a cyclic number.

It is not a de Polignac number, because 2443257661 - 2¹⁵ = 2443224893 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2443257601) 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, 93971436 + ... + 93971461.

It is an arithmetic number, because the mean of its divisors is an integer number (657800143).

Almost surely, 2^2443257661 is an apocalyptic number.

It is an amenable number.

2443257661 is a deficient number, since it is larger than the sum of its proper divisors (187942911).

2443257661 is a wasteful number, since it uses less digits than its factorization.

2443257661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187942910.

The product of its digits is 241920, while the sum is 40.

The square root of 2443257661 is about 49429.3198516832. The cubic root of 2443257661 is about 1346.8619680954.

The spelling of 2443257661 in words is "two billion, four hundred forty-three million, two hundred fifty-seven thousand, six hundred sixty-one".