21050505021331 has 4 divisors (see below), whose sum is σ = 21050536483872. Its totient is φ = 21050473558792.

The previous prime is 21050505021323. The next prime is 21050505021349. The reversal of 21050505021331 is 13312050505012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21050505021331 - 2³ = 21050505021323 is a prime.

It is a super-2 number, since 2×21050505021331² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21050505021331.

It is not an unprimeable number, because it can be changed into a prime (21050505021631) 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, 14705371 + ... + 16073236.

It is an arithmetic number, because the mean of its divisors is an integer number (5262634120968).

Almost surely, 2^{21050505021331} is an apocalyptic number.

21050505021331 is a deficient number, since it is larger than the sum of its proper divisors (31462541).

21050505021331 is an equidigital number, since it uses as much as digits as its factorization.

21050505021331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31462540.

The product of its (nonzero) digits is 4500, while the sum is 28.

Adding to 21050505021331 its reverse (13312050505012), we get a palindrome (34362555526343).

The spelling of 21050505021331 in words is "twenty-one trillion, fifty billion, five hundred five million, twenty-one thousand, three hundred thirty-one".