381551616 has 132 divisors (see below), whose sum is σ = 1160239600. Its totient is φ = 120434688.

The previous prime is 381551591. The next prime is 381551641. The reversal of 381551616 is 616155183.

381551616 is a `hidden beast` number, since 38 + 1 + 5 + 5 + 1 + 616 = 666.

It is an interprime number because it is at equal distance from previous prime (381551591) and next prime (381551641).

It is a super-4 number, since 4×381551616⁴ (a number of 35 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 174015 + ... + 176193.

Almost surely, 2^381551616 is an apocalyptic number.

381551616 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 381551616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (580119800).

381551616 is an abundant number, since it is smaller than the sum of its proper divisors (778687984).

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

381551616 is a wasteful number, since it uses less digits than its factorization.

381551616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2224 (or 2203 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

The square root of 381551616 is about 19533.3462571061. The cubic root of 381551616 is about 725.3001474628.

The spelling of 381551616 in words is "three hundred eighty-one million, five hundred fifty-one thousand, six hundred sixteen".