189790421 has 2 divisors, whose sum is σ = 189790422. Its totient is φ = 189790420.

The previous prime is 189790409. The next prime is 189790429. The reversal of 189790421 is 124097981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 109956196 + 79834225 = 10486^2 + 8935^2 .

It is a cyclic number.

It is not a de Polignac number, because 189790421 - 2⁶ = 189790357 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (189790429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94895210 + 94895211.

It is an arithmetic number, because the mean of its divisors is an integer number (94895211).

Almost surely, 2^189790421 is an apocalyptic number.

It is an amenable number.

189790421 is a deficient number, since it is larger than the sum of its proper divisors (1).

189790421 is an equidigital number, since it uses as much as digits as its factorization.

189790421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36288, while the sum is 41.

The square root of 189790421 is about 13776.4444251773. Note that the first 4 decimals coincide. The cubic root of 189790421 is about 574.6782532674.

The spelling of 189790421 in words is "one hundred eighty-nine million, seven hundred ninety thousand, four hundred twenty-one".