21545503155 has 24 divisors (see below), whose sum is σ = 40740588720. Its totient is φ = 10446304320.

The previous prime is 21545503151. The next prime is 21545503171. The reversal of 21545503155 is 55130554512.

21545503155 is a `hidden beast` number, since 2 + 1 + 54 + 550 + 3 + 1 + 55 = 666.

It is not a de Polignac number, because 21545503155 - 2² = 21545503151 is a prime.

It is a super-2 number, since 2×21545503155² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21545503151) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21762640 + ... + 21763629.

It is an arithmetic number, because the mean of its divisors is an integer number (1697524530).

Almost surely, 2^21545503155 is an apocalyptic number.

21545503155 is a deficient number, since it is larger than the sum of its proper divisors (19195085565).

21545503155 is a wasteful number, since it uses less digits than its factorization.

21545503155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43526291 (or 43526288 counting only the distinct ones).

The product of its (nonzero) digits is 75000, while the sum is 36.

The spelling of 21545503155 in words is "twenty-one billion, five hundred forty-five million, five hundred three thousand, one hundred fifty-five".