21115500155 has 8 divisors (see below), whose sum is σ = 26212345200. Its totient is φ = 16309903456.

The previous prime is 21115500151. The next prime is 21115500157. The reversal of 21115500155 is 55100551112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21115500155 - 2² = 21115500151 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21115500151) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 72811925 + ... + 72812214.

It is an arithmetic number, because the mean of its divisors is an integer number (3276543150).

Almost surely, 2^21115500155 is an apocalyptic number.

21115500155 is a deficient number, since it is larger than the sum of its proper divisors (5096845045).

21115500155 is a wasteful number, since it uses less digits than its factorization.

21115500155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145624173.

The product of its (nonzero) digits is 1250, while the sum is 26.

The spelling of 21115500155 in words is "twenty-one billion, one hundred fifteen million, five hundred thousand, one hundred fifty-five".