21613031611 has 4 divisors (see below), whose sum is σ = 21708243432. Its totient is φ = 21517819792.

The previous prime is 21613031599. The next prime is 21613031681. The reversal of 21613031611 is 11613031612.

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 21613031611 - 2²¹ = 21610934459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21613031681) 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, 47605570 + ... + 47606023.

It is an arithmetic number, because the mean of its divisors is an integer number (5427060858).

Almost surely, 2^21613031611 is an apocalyptic number.

21613031611 is a deficient number, since it is larger than the sum of its proper divisors (95211821).

21613031611 is an equidigital number, since it uses as much as digits as its factorization.

21613031611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95211820.

The product of its (nonzero) digits is 648, while the sum is 25.

Subtracting from 21613031611 its reverse (11613031612), we obtain a palindrome (9999999999).

The spelling of 21613031611 in words is "twenty-one billion, six hundred thirteen million, thirty-one thousand, six hundred eleven".