20381399 has 2 divisors, whose sum is σ = 20381400. Its totient is φ = 20381398.

The previous prime is 20381369. The next prime is 20381401. The reversal of 20381399 is 99318302.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20381399 is a prime.

Together with 20381401, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20381329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10190699 + 10190700.

It is an arithmetic number, because the mean of its divisors is an integer number (10190700).

Almost surely, 2^20381399 is an apocalyptic number.

20381399 is a deficient number, since it is larger than the sum of its proper divisors (1).

20381399 is an equidigital number, since it uses as much as digits as its factorization.

20381399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 20381399 is about 4514.5762813358. The cubic root of 20381399 is about 273.1563685309.

The spelling of 20381399 in words is "twenty million, three hundred eighty-one thousand, three hundred ninety-nine".