18456621721545 has 16 divisors (see below), whose sum is σ = 33749251148160. Its totient is φ = 8437312786944.

The previous prime is 18456621721529. The next prime is 18456621721547. The reversal of 18456621721545 is 54512712665481.

It is not a de Polignac number, because 18456621721545 - 2⁴ = 18456621721529 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18456621721547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87888674760 + ... + 87888674969.

It is an arithmetic number, because the mean of its divisors is an integer number (2109328196760).

Almost surely, 2^{18456621721545} is an apocalyptic number.

18456621721545 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18456621721545 is a deficient number, since it is larger than the sum of its proper divisors (15292629426615).

18456621721545 is a wasteful number, since it uses less digits than its factorization.

18456621721545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175777349744.

The product of its digits is 16128000, while the sum is 57.

The spelling of 18456621721545 in words is "eighteen trillion, four hundred fifty-six billion, six hundred twenty-one million, seven hundred twenty-one thousand, five hundred forty-five".