387987781 has 12 divisors (see below), whose sum is σ = 404840800. Its totient is φ = 371801808.

The previous prime is 387987767. The next prime is 387987791. The reversal of 387987781 is 187789783.

It is not a de Polignac number, because 387987781 - 2⁹ = 387987269 is a prime.

It is a super-2 number, since 2×387987781² = 301069036410607922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (387987701) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 115240 + ... + 118558.

Almost surely, 2^387987781 is an apocalyptic number.

It is an amenable number.

387987781 is a deficient number, since it is larger than the sum of its proper divisors (16853019).

387987781 is a wasteful number, since it uses less digits than its factorization.

387987781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3516 (or 3487 counting only the distinct ones).

The product of its digits is 4741632, while the sum is 58.

The square root of 387987781 is about 19697.4054382804. The cubic root of 387987781 is about 729.3556464616.

The spelling of 387987781 in words is "three hundred eighty-seven million, nine hundred eighty-seven thousand, seven hundred eighty-one".