381421981 has 2 divisors, whose sum is σ = 381421982. Its totient is φ = 381421980.

The previous prime is 381421933. The next prime is 381421991. The reversal of 381421981 is 189124183.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 380835225 + 586756 = 19515^2 + 766^2 .

It is a cyclic number.

It is not a de Polignac number, because 381421981 - 2¹⁵ = 381389213 is a prime.

It is a super-2 number, since 2×381421981² = 290965455179928722, 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 381421981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (381421921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 190710990 + 190710991.

It is an arithmetic number, because the mean of its divisors is an integer number (190710991).

Almost surely, 2^381421981 is an apocalyptic number.

It is an amenable number.

381421981 is a deficient number, since it is larger than the sum of its proper divisors (1).

381421981 is an equidigital number, since it uses as much as digits as its factorization.

381421981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13824, while the sum is 37.

The square root of 381421981 is about 19530.0276753516. The cubic root of 381421981 is about 725.2179961180.

The spelling of 381421981 in words is "three hundred eighty-one million, four hundred twenty-one thousand, nine hundred eighty-one".