18666720535 has 16 divisors (see below), whose sum is σ = 23379010560. Its totient is φ = 14281025440.

The previous prime is 18666720491. The next prime is 18666720559. The reversal of 18666720535 is 53502766681.

It is not a de Polignac number, because 18666720535 - 2²³ = 18658331927 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 619980 + ... + 649390.

It is an arithmetic number, because the mean of its divisors is an integer number (1461188160).

Almost surely, 2^18666720535 is an apocalyptic number.

18666720535 is a deficient number, since it is larger than the sum of its proper divisors (4712290025).

18666720535 is a wasteful number, since it uses less digits than its factorization.

18666720535 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34958.

The product of its (nonzero) digits is 1814400, while the sum is 49.

The spelling of 18666720535 in words is "eighteen billion, six hundred sixty-six million, seven hundred twenty thousand, five hundred thirty-five".