21115733545 has 32 divisors (see below), whose sum is σ = 26432649216. Its totient is φ = 16175808000.

The previous prime is 21115733539. The next prime is 21115733549. The reversal of 21115733545 is 54533751112.

It is not a de Polignac number, because 21115733545 - 2⁹ = 21115733033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21115733549) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6481557 + ... + 6484813.

It is an arithmetic number, because the mean of its divisors is an integer number (826020288).

Almost surely, 2^21115733545 is an apocalyptic number.

It is an amenable number.

21115733545 is a deficient number, since it is larger than the sum of its proper divisors (5316915671).

21115733545 is a wasteful number, since it uses less digits than its factorization.

21115733545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3721.

The product of its digits is 63000, while the sum is 37.

The spelling of 21115733545 in words is "twenty-one billion, one hundred fifteen million, seven hundred thirty-three thousand, five hundred forty-five".