2661609217438 has 4 divisors (see below), whose sum is σ = 3992413826160. Its totient is φ = 1330804608718.

The previous prime is 2661609217429. The next prime is 2661609217453. The reversal of 2661609217438 is 8347129061662.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665402304358 + ... + 665402304361.

It is an arithmetic number, because the mean of its divisors is an integer number (998103456540).

Almost surely, 2^{2661609217438} is an apocalyptic number.

2661609217438 is a deficient number, since it is larger than the sum of its proper divisors (1330804608722).

2661609217438 is a wasteful number, since it uses less digits than its factorization.

2661609217438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1330804608721.

The product of its (nonzero) digits is 5225472, while the sum is 55.

The spelling of 2661609217438 in words is "two trillion, six hundred sixty-one billion, six hundred nine million, two hundred seventeen thousand, four hundred thirty-eight".