21504031020055 has 8 divisors (see below), whose sum is σ = 26115738877872. Its totient is φ = 16995957046848.

The previous prime is 21504031020049. The next prime is 21504031020107. The reversal of 21504031020055 is 55002013040512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21504031020055 - 2¹⁵ = 21504030987287 is a prime.

It is a super-2 number, since 2×21504031020055² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25908470694 + ... + 25908471523.

It is an arithmetic number, because the mean of its divisors is an integer number (3264467359734).

Almost surely, 2^{21504031020055} is an apocalyptic number.

21504031020055 is a deficient number, since it is larger than the sum of its proper divisors (4611707857817).

21504031020055 is an equidigital number, since it uses as much as digits as its factorization.

21504031020055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51816942305.

The product of its (nonzero) digits is 6000, while the sum is 28.

Adding to 21504031020055 its reverse (55002013040512), we get a palindrome (76506044060567).

The spelling of 21504031020055 in words is "twenty-one trillion, five hundred four billion, thirty-one million, twenty thousand, fifty-five".