1665415538918 has 4 divisors (see below), whose sum is σ = 2498123308380. Its totient is φ = 832707769458.

The previous prime is 1665415538909. The next prime is 1665415538933. The reversal of 1665415538918 is 8198355145661.

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

It is a super-2 number, since 2×1665415538918² (a number of 25 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 416353884728 + ... + 416353884731.

It is an arithmetic number, because the mean of its divisors is an integer number (624530827095).

Almost surely, 2^{1665415538918} is an apocalyptic number.

1665415538918 is a deficient number, since it is larger than the sum of its proper divisors (832707769462).

1665415538918 is an equidigital number, since it uses as much as digits as its factorization.

1665415538918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 832707769461.

The product of its digits is 31104000, while the sum is 62.

The spelling of 1665415538918 in words is "one trillion, six hundred sixty-five billion, four hundred fifteen million, five hundred thirty-eight thousand, nine hundred eighteen".