381661009920 has 1344 divisors, whose sum is σ = 1488841754400. Its totient is φ = 93640458240.

The previous prime is 381661009913. The next prime is 381661010047. The reversal of 381661009920 is 29900166183.

It is a happy number.

381661009920 is a `hidden beast` number, since 3 + 8 + 1 + 6 + 610 + 0 + 9 + 9 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 8875837419 + ... + 8875837461.

Almost surely, 2^381661009920 is an apocalyptic number.

381661009920 is a gapful number since it is divisible by the number (30) 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 381661009920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (744420877200).

381661009920 is an abundant number, since it is smaller than the sum of its proper divisors (1107180744480).

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

381661009920 is an equidigital number, since it uses as much as digits as its factorization.

381661009920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158 (or 123 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The spelling of 381661009920 in words is "three hundred eighty-one billion, six hundred sixty-one million, nine thousand, nine hundred twenty".