206971381 has 2 divisors, whose sum is σ = 206971382. Its totient is φ = 206971380.

The previous prime is 206971367. The next prime is 206971397. The reversal of 206971381 is 183179602.

206971381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 135839025 + 71132356 = 11655^2 + 8434^2 .

It is a cyclic number.

It is not a de Polignac number, because 206971381 - 2¹³ = 206963189 is a prime.

It is a super-2 number, since 2×206971381² = 85674305106094322, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 206971381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206971361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103485690 + 103485691.

It is an arithmetic number, because the mean of its divisors is an integer number (103485691).

Almost surely, 2^206971381 is an apocalyptic number.

It is an amenable number.

206971381 is a deficient number, since it is larger than the sum of its proper divisors (1).

206971381 is an equidigital number, since it uses as much as digits as its factorization.

206971381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 206971381 is about 14386.4999565565. The cubic root of 206971381 is about 591.5209070114.

The spelling of 206971381 in words is "two hundred six million, nine hundred seventy-one thousand, three hundred eighty-one".