21031200061 has 2 divisors, whose sum is σ = 21031200062. Its totient is φ = 21031200060.

The previous prime is 21031200019. The next prime is 21031200101. The reversal of 21031200061 is 16000213012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12118707225 + 8912492836 = 110085^2 + 94406^2 .

It is a cyclic number.

It is not a de Polignac number, because 21031200061 - 2³³ = 12441265469 is a prime.

It is a super-2 number, since 2×21031200061² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21031800061) 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, 10515600030 + 10515600031.

It is an arithmetic number, because the mean of its divisors is an integer number (10515600031).

Almost surely, 2^21031200061 is an apocalyptic number.

It is an amenable number.

21031200061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21031200061 is an equidigital number, since it uses as much as digits as its factorization.

21031200061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21031200061 its reverse (16000213012), we get a palindrome (37031413073).

The spelling of 21031200061 in words is "twenty-one billion, thirty-one million, two hundred thousand, sixty-one".