387667781 has 2 divisors, whose sum is σ = 387667782. Its totient is φ = 387667780.

The previous prime is 387667727. The next prime is 387667789. The reversal of 387667781 is 187766783.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 331567681 + 56100100 = 18209^2 + 7490^2 .

It is a cyclic number.

It is not a de Polignac number, because 387667781 - 2⁶ = 387667717 is a prime.

It is a super-2 number, since 2×387667781² = 300572616850927922, 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 (387667789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 193833890 + 193833891.

It is an arithmetic number, because the mean of its divisors is an integer number (193833891).

Almost surely, 2^387667781 is an apocalyptic number.

It is an amenable number.

387667781 is a deficient number, since it is larger than the sum of its proper divisors (1).

387667781 is an equidigital number, since it uses as much as digits as its factorization.

387667781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2370816, while the sum is 53.

The square root of 387667781 is about 19689.2808654862. The cubic root of 387667781 is about 729.1550748517.

The spelling of 387667781 in words is "three hundred eighty-seven million, six hundred sixty-seven thousand, seven hundred eighty-one".