381821556 has 12 divisors (see below), whose sum is σ = 890916992. Its totient is φ = 127273848.

The previous prime is 381821519. The next prime is 381821579. The reversal of 381821556 is 655128183.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×381821556² = 291575401252522272, which contains 22 as substring.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15909220 + ... + 15909243.

Almost surely, 2^381821556 is an apocalyptic number.

It is an amenable number.

381821556 is an abundant number, since it is smaller than the sum of its proper divisors (509095436).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

381821556 is a wasteful number, since it uses less digits than its factorization.

381821556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31818470 (or 31818468 counting only the distinct ones).

The product of its digits is 57600, while the sum is 39.

The square root of 381821556 is about 19540.2547578070. The cubic root of 381821556 is about 725.4711521709.

The spelling of 381821556 in words is "three hundred eighty-one million, eight hundred twenty-one thousand, five hundred fifty-six".