21056010613 has 4 divisors (see below), whose sum is σ = 22970193408. Its totient is φ = 19141827820.

The previous prime is 21056010611. The next prime is 21056010631. The reversal of 21056010613 is 31601065012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21056010613 - 2¹ = 21056010611 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056010611) 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, 957091381 + ... + 957091402.

It is an arithmetic number, because the mean of its divisors is an integer number (5742548352).

Almost surely, 2^21056010613 is an apocalyptic number.

It is an amenable number.

21056010613 is a deficient number, since it is larger than the sum of its proper divisors (1914182795).

21056010613 is a wasteful number, since it uses less digits than its factorization.

21056010613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1914182794.

The product of its (nonzero) digits is 1080, while the sum is 25.

Adding to 21056010613 its reverse (31601065012), we get a palindrome (52657075625).

The spelling of 21056010613 in words is "twenty-one billion, fifty-six million, ten thousand, six hundred thirteen".