21031220344555 has 32 divisors (see below), whose sum is σ = 25739149363200. Its totient is φ = 16493782660992.

The previous prime is 21031220344553. The next prime is 21031220344567. The reversal of 21031220344555 is 55544302213012.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21031220344555 - 2¹ = 21031220344553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21031220344553) 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, 58066561 + ... + 58427629.

It is an arithmetic number, because the mean of its divisors is an integer number (804348417600).

Almost surely, 2^{21031220344555} is an apocalyptic number.

21031220344555 is a deficient number, since it is larger than the sum of its proper divisors (4707929018645).

21031220344555 is a wasteful number, since it uses less digits than its factorization.

21031220344555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362203.

The product of its (nonzero) digits is 144000, while the sum is 37.

Adding to 21031220344555 its reverse (55544302213012), we get a palindrome (76575522557567).

The spelling of 21031220344555 in words is "twenty-one trillion, thirty-one billion, two hundred twenty million, three hundred forty-four thousand, five hundred fifty-five".