21050042340511 has 4 divisors (see below), whose sum is σ = 21095704038024. Its totient is φ = 21004380643000.

The previous prime is 21050042340421. The next prime is 21050042340553. The reversal of 21050042340511 is 11504324005012.

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 21050042340511 - 2¹⁵ = 21050042307743 is a prime.

It is a super-2 number, since 2×21050042340511² (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 21050042340511.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21050042340011) 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, 22830848065 + ... + 22830848986.

It is an arithmetic number, because the mean of its divisors is an integer number (5273926009506).

Almost surely, 2^{21050042340511} is an apocalyptic number.

21050042340511 is a deficient number, since it is larger than the sum of its proper divisors (45661697513).

21050042340511 is an equidigital number, since it uses as much as digits as its factorization.

21050042340511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45661697512.

The product of its (nonzero) digits is 4800, while the sum is 28.

Adding to 21050042340511 its reverse (11504324005012), we get a palindrome (32554366345523).

The spelling of 21050042340511 in words is "twenty-one trillion, fifty billion, forty-two million, three hundred forty thousand, five hundred eleven".