193213981 has 2 divisors, whose sum is σ = 193213982. Its totient is φ = 193213980.

The previous prime is 193213973. The next prime is 193213987. The reversal of 193213981 is 189312391.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 146168100 + 47045881 = 12090^2 + 6859^2 .

It is a cyclic number.

It is not a de Polignac number, because 193213981 - 2³ = 193213973 is a prime.

It is a super-2 number, since 2×193213981² = 74663284907736722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 193213981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (193213987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 96606990 + 96606991.

It is an arithmetic number, because the mean of its divisors is an integer number (96606991).

Almost surely, 2^193213981 is an apocalyptic number.

It is an amenable number.

193213981 is a deficient number, since it is larger than the sum of its proper divisors (1).

193213981 is an equidigital number, since it uses as much as digits as its factorization.

193213981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11664, while the sum is 37.

The square root of 193213981 is about 13900.1432007012. The cubic root of 193213981 is about 578.1131519792.

The spelling of 193213981 in words is "one hundred ninety-three million, two hundred thirteen thousand, nine hundred eighty-one".