194688521 has 2 divisors, whose sum is σ = 194688522. Its totient is φ = 194688520.

The previous prime is 194688493. The next prime is 194688569. The reversal of 194688521 is 125886491.

194688521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 186622921 + 8065600 = 13661^2 + 2840^2 .

It is an emirp because it is prime and its reverse (125886491) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 194688521 - 2²⁶ = 127579657 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (194688581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97344260 + 97344261.

It is an arithmetic number, because the mean of its divisors is an integer number (97344261).

Almost surely, 2^194688521 is an apocalyptic number.

It is an amenable number.

194688521 is a deficient number, since it is larger than the sum of its proper divisors (1).

194688521 is an equidigital number, since it uses as much as digits as its factorization.

194688521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 138240, while the sum is 44.

The square root of 194688521 is about 13953.0828493204. The cubic root of 194688521 is about 579.5800775380.

The spelling of 194688521 in words is "one hundred ninety-four million, six hundred eighty-eight thousand, five hundred twenty-one".