381613781 has 2 divisors, whose sum is σ = 381613782. Its totient is φ = 381613780.

The previous prime is 381613747. The next prime is 381613787. The reversal of 381613781 is 187316183.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 369600625 + 12013156 = 19225^2 + 3466^2 .

It is a cyclic number.

It is not a de Polignac number, because 381613781 - 2⁶ = 381613717 is a prime.

It is a super-2 number, since 2×381613781² = 291258155698231922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (381613787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 190806890 + 190806891.

It is an arithmetic number, because the mean of its divisors is an integer number (190806891).

Almost surely, 2^381613781 is an apocalyptic number.

It is an amenable number.

381613781 is a deficient number, since it is larger than the sum of its proper divisors (1).

381613781 is an equidigital number, since it uses as much as digits as its factorization.

381613781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192, while the sum is 38.

The square root of 381613781 is about 19534.9374455103. The cubic root of 381613781 is about 725.3395356114.

The spelling of 381613781 in words is "three hundred eighty-one million, six hundred thirteen thousand, seven hundred eighty-one".