21213544064155 has 32 divisors (see below), whose sum is σ = 26168937338880. Its totient is φ = 16500581086080.

The previous prime is 21213544064149. The next prime is 21213544064159. The reversal of 21213544064155 is 55146044531212.

It is not a de Polignac number, because 21213544064155 - 2⁵ = 21213544064123 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21213544064159) 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, 66911560 + ... + 67227850.

It is an arithmetic number, because the mean of its divisors is an integer number (817779291840).

Almost surely, 2^{21213544064155} is an apocalyptic number.

21213544064155 is a deficient number, since it is larger than the sum of its proper divisors (4955393274725).

21213544064155 is a wasteful number, since it uses less digits than its factorization.

21213544064155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318219.

The product of its (nonzero) digits is 576000, while the sum is 43.

Adding to 21213544064155 its reverse (55146044531212), we get a palindrome (76359588595367).

The spelling of 21213544064155 in words is "twenty-one trillion, two hundred thirteen billion, five hundred forty-four million, sixty-four thousand, one hundred fifty-five".