21044531203655 has 64 divisors (see below), whose sum is σ = 27020274285312. Its totient is φ = 15679391170560.

The previous prime is 21044531203651. The next prime is 21044531203667. The reversal of 21044531203655 is 55630213544012.

It is not a de Polignac number, because 21044531203655 - 2² = 21044531203651 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21044531203651) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 9829298885 + ... + 9829301025.

It is an arithmetic number, because the mean of its divisors is an integer number (422191785708).

Almost surely, 2^{21044531203655} is an apocalyptic number.

21044531203655 is a deficient number, since it is larger than the sum of its proper divisors (5975743081657).

21044531203655 is a wasteful number, since it uses less digits than its factorization.

21044531203655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4604.

The product of its (nonzero) digits is 432000, while the sum is 41.

Adding to 21044531203655 its reverse (55630213544012), we get a palindrome (76674744747667).

The spelling of 21044531203655 in words is "twenty-one trillion, forty-four billion, five hundred thirty-one million, two hundred three thousand, six hundred fifty-five".