21284940511 has 4 divisors (see below), whose sum is σ = 21633874024. Its totient is φ = 20936007000.

The previous prime is 21284940499. The next prime is 21284940529. The reversal of 21284940511 is 11504948212.

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 21284940511 - 2¹¹ = 21284938463 is a prime.

It is a super-2 number, since 2×21284940511² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21284940571) 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, 174466665 + ... + 174466786.

It is an arithmetic number, because the mean of its divisors is an integer number (5408468506).

Almost surely, 2^21284940511 is an apocalyptic number.

21284940511 is a deficient number, since it is larger than the sum of its proper divisors (348933513).

21284940511 is an equidigital number, since it uses as much as digits as its factorization.

21284940511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 348933512.

The product of its (nonzero) digits is 23040, while the sum is 37.

The spelling of 21284940511 in words is "twenty-one billion, two hundred eighty-four million, nine hundred forty thousand, five hundred eleven".