20541221155 has 24 divisors (see below), whose sum is σ = 30879554832. Its totient is φ = 13001913792.

The previous prime is 20541221153. The next prime is 20541221161. The reversal of 20541221155 is 55112214502.

It is not a de Polignac number, because 20541221155 - 2¹ = 20541221153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20541221153) 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, 3221497 + ... + 3227866.

It is an arithmetic number, because the mean of its divisors is an integer number (1286648118).

Almost surely, 2^20541221155 is an apocalyptic number.

20541221155 is a deficient number, since it is larger than the sum of its proper divisors (10338333677).

20541221155 is a wasteful number, since it uses less digits than its factorization.

20541221155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6449395 (or 6449388 counting only the distinct ones).

The product of its (nonzero) digits is 4000, while the sum is 28.

Adding to 20541221155 its reverse (55112214502), we get a palindrome (75653435657).

The spelling of 20541221155 in words is "twenty billion, five hundred forty-one million, two hundred twenty-one thousand, one hundred fifty-five".