21520541411 has 4 divisors (see below), whose sum is σ = 21520988424. Its totient is φ = 21520094400.

The previous prime is 21520541381. The next prime is 21520541423. The reversal of 21520541411 is 11414502512.

It is a happy number.

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 21520541411 - 2²² = 21516347107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21520541431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141185 + ... + 250946.

It is an arithmetic number, because the mean of its divisors is an integer number (5380247106).

Almost surely, 2^21520541411 is an apocalyptic number.

21520541411 is a deficient number, since it is larger than the sum of its proper divisors (447013).

21520541411 is an equidigital number, since it uses as much as digits as its factorization.

21520541411 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 447012.

The product of its (nonzero) digits is 1600, while the sum is 26.

The spelling of 21520541411 in words is "twenty-one billion, five hundred twenty million, five hundred forty-one thousand, four hundred eleven".