21555355020013 has 4 divisors (see below), whose sum is σ = 21555595192608. Its totient is φ = 21555114847420.

The previous prime is 21555355019977. The next prime is 21555355020029. The reversal of 21555355020013 is 31002055355512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21555355020013 - 2²⁹ = 21554818149101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21555355050013) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 119951623 + ... + 120131188.

It is an arithmetic number, because the mean of its divisors is an integer number (5388898798152).

Almost surely, 2^{21555355020013} is an apocalyptic number.

It is an amenable number.

21555355020013 is a deficient number, since it is larger than the sum of its proper divisors (240172595).

21555355020013 is an equidigital number, since it uses as much as digits as its factorization.

21555355020013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240172594.

The product of its (nonzero) digits is 112500, while the sum is 37.

The spelling of 21555355020013 in words is "twenty-one trillion, five hundred fifty-five billion, three hundred fifty-five million, twenty thousand, thirteen".