21101100061 has 2 divisors, whose sum is σ = 21101100062. Its totient is φ = 21101100060.

The previous prime is 21101099989. The next prime is 21101100073. The reversal of 21101100061 is 16000110112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14765895225 + 6335204836 = 121515^2 + 79594^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101100061 - 2¹¹ = 21101098013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21101100661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550550030 + 10550550031.

It is an arithmetic number, because the mean of its divisors is an integer number (10550550031).

Almost surely, 2^21101100061 is an apocalyptic number.

It is an amenable number.

21101100061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101100061 is an equidigital number, since it uses as much as digits as its factorization.

21101100061 is an odious number, because the sum of its binary digits is odd.

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

Adding to 21101100061 its reverse (16000110112), we get a palindrome (37101210173).

The spelling of 21101100061 in words is "twenty-one billion, one hundred one million, one hundred thousand, sixty-one".