194847721 has 2 divisors, whose sum is σ = 194847722. Its totient is φ = 194847720.

The previous prime is 194847713. The next prime is 194847797. The reversal of 194847721 is 127748491.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 136539225 + 58308496 = 11685^2 + 7636^2 .

It is a cyclic number.

It is not a de Polignac number, because 194847721 - 2³ = 194847713 is a prime.

It is not a weakly prime, because it can be changed into another prime (194847221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97423860 + 97423861.

It is an arithmetic number, because the mean of its divisors is an integer number (97423861).

Almost surely, 2^194847721 is an apocalyptic number.

It is an amenable number.

194847721 is a deficient number, since it is larger than the sum of its proper divisors (1).

194847721 is an equidigital number, since it uses as much as digits as its factorization.

194847721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 112896, while the sum is 43.

The square root of 194847721 is about 13958.7865160264. The cubic root of 194847721 is about 579.7380118790.

The spelling of 194847721 in words is "one hundred ninety-four million, eight hundred forty-seven thousand, seven hundred twenty-one".