21711611 has 2 divisors, whose sum is σ = 21711612. Its totient is φ = 21711610.

The previous prime is 21711589. The next prime is 21711619. The reversal of 21711611 is 11611712.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21711611 is a prime.

It is not a weakly prime, because it can be changed into another prime (21711619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10855805 + 10855806.

It is an arithmetic number, because the mean of its divisors is an integer number (10855806).

Almost surely, 2^21711611 is an apocalyptic number.

21711611 is a deficient number, since it is larger than the sum of its proper divisors (1).

21711611 is an equidigital number, since it uses as much as digits as its factorization.

21711611 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84, while the sum is 20.

The square root of 21711611 is about 4659.5719760510. The cubic root of 21711611 is about 278.9741843082.

It can be divided in two parts, 21711 and 611, that added together give a palindrome (22322).

The spelling of 21711611 in words is "twenty-one million, seven hundred eleven thousand, six hundred eleven".