193400821 has 2 divisors, whose sum is σ = 193400822. Its totient is φ = 193400820.

The previous prime is 193400819. The next prime is 193400833. The reversal of 193400821 is 128004391.

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., 161036100 + 32364721 = 12690^2 + 5689^2 .

It is a cyclic number.

It is not a de Polignac number, because 193400821 - 2¹ = 193400819 is a prime.

Together with 193400819, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 193400821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (193400881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 96700410 + 96700411.

It is an arithmetic number, because the mean of its divisors is an integer number (96700411).

Almost surely, 2^193400821 is an apocalyptic number.

It is an amenable number.

193400821 is a deficient number, since it is larger than the sum of its proper divisors (1).

193400821 is an equidigital number, since it uses as much as digits as its factorization.

193400821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 193400821 is about 13906.8623707866. The cubic root of 193400821 is about 578.2994391591.

The spelling of 193400821 in words is "one hundred ninety-three million, four hundred thousand, eight hundred twenty-one".