194123821 has 2 divisors, whose sum is σ = 194123822. Its totient is φ = 194123820.

The previous prime is 194123773. The next prime is 194123827. The reversal of 194123821 is 128321491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 158482921 + 35640900 = 12589^2 + 5970^2 .

It is a cyclic number.

It is not a de Polignac number, because 194123821 - 2¹³ = 194115629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (194123827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97061910 + 97061911.

It is an arithmetic number, because the mean of its divisors is an integer number (97061911).

Almost surely, 2^194123821 is an apocalyptic number.

It is an amenable number.

194123821 is a deficient number, since it is larger than the sum of its proper divisors (1).

194123821 is an equidigital number, since it uses as much as digits as its factorization.

194123821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 31.

The square root of 194123821 is about 13932.8324830237. The cubic root of 194123821 is about 579.0191716422.

The spelling of 194123821 in words is "one hundred ninety-four million, one hundred twenty-three thousand, eight hundred twenty-one".