21056605343 has 4 divisors (see below), whose sum is σ = 21056913768. Its totient is φ = 21056296920.

The previous prime is 21056605333. The next prime is 21056605417. The reversal of 21056605343 is 34350665012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21056605343 - 2²⁴ = 21039828127 is a prime.

It is a super-2 number, since 2×21056605343² (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 (21056605303) 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, 1193 + ... + 205218.

It is an arithmetic number, because the mean of its divisors is an integer number (5264228442).

Almost surely, 2^21056605343 is an apocalyptic number.

21056605343 is a deficient number, since it is larger than the sum of its proper divisors (308425).

21056605343 is a wasteful number, since it uses less digits than its factorization.

21056605343 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308424.

The product of its (nonzero) digits is 64800, while the sum is 35.

The spelling of 21056605343 in words is "twenty-one billion, fifty-six million, six hundred five thousand, three hundred forty-three".