102111721 has 2 divisors, whose sum is σ = 102111722. Its totient is φ = 102111720.

The previous prime is 102111677. The next prime is 102111727. The reversal of 102111721 is 127111201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 101707225 + 404496 = 10085^2 + 636^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-102111721 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 102111695 and 102111704.

It is not a weakly prime, because it can be changed into another prime (102111727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51055860 + 51055861.

It is an arithmetic number, because the mean of its divisors is an integer number (51055861).

Almost surely, 2^102111721 is an apocalyptic number.

It is an amenable number.

102111721 is a deficient number, since it is larger than the sum of its proper divisors (1).

102111721 is an equidigital number, since it uses as much as digits as its factorization.

102111721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28, while the sum is 16.

The square root of 102111721 is about 10105.0344383381. The cubic root of 102111721 is about 467.4033979244.

Adding to 102111721 its reverse (127111201), we get a palindrome (229222922).

The spelling of 102111721 in words is "one hundred two million, one hundred eleven thousand, seven hundred twenty-one".