9921688061 has 2 divisors, whose sum is σ = 9921688062. Its totient is φ = 9921688060.

The previous prime is 9921688057. The next prime is 9921688093. The reversal of 9921688061 is 1608861299.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9825765625 + 95922436 = 99125^2 + 9794^2 .

It is a cyclic number.

It is not a de Polignac number, because 9921688061 - 2² = 9921688057 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9921688001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4960844030 + 4960844031.

It is an arithmetic number, because the mean of its divisors is an integer number (4960844031).

Almost surely, 2^9921688061 is an apocalyptic number.

It is an amenable number.

9921688061 is a deficient number, since it is larger than the sum of its proper divisors (1).

9921688061 is an equidigital number, since it uses as much as digits as its factorization.

9921688061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 373248, while the sum is 50.

The square root of 9921688061 is about 99607.6706935766. The cubic root of 9921688061 is about 2148.7960131911.

The spelling of 9921688061 in words is "nine billion, nine hundred twenty-one million, six hundred eighty-eight thousand, sixty-one".