21111061 has 2 divisors, whose sum is σ = 21111062. Its totient is φ = 21111060.

The previous prime is 21111049. The next prime is 21111073. The reversal of 21111061 is 16011112.

It is a balanced prime because it is at equal distance from previous prime (21111049) and next prime (21111073).

It can be written as a sum of positive squares in only one way, i.e., 18879025 + 2232036 = 4345^2 + 1494^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111061 - 2⁵ = 21111029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21112061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555530 + 10555531.

It is an arithmetic number, because the mean of its divisors is an integer number (10555531).

Almost surely, 2^21111061 is an apocalyptic number.

It is an amenable number.

21111061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111061 is an equidigital number, since it uses as much as digits as its factorization.

21111061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12, while the sum is 13.

The square root of 21111061 is about 4594.6774641970. The cubic root of 21111061 is about 276.3779260500.

Adding to 21111061 its reverse (16011112), we get a palindrome (37122173).

The spelling of 21111061 in words is "twenty-one million, one hundred eleven thousand, sixty-one".