381290721 has 8 divisors (see below), whose sum is σ = 581014464. Its totient is φ = 217880400.

The previous prime is 381290719. The next prime is 381290737. The reversal of 381290721 is 127092183.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 381290721 - 2¹ = 381290719 is a prime.

It is a super-2 number, since 2×381290721² = 290765227841399682, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (381290771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9078330 + ... + 9078371.

It is an arithmetic number, because the mean of its divisors is an integer number (72626808).

Almost surely, 2^381290721 is an apocalyptic number.

It is an amenable number.

381290721 is a deficient number, since it is larger than the sum of its proper divisors (199723743).

381290721 is a wasteful number, since it uses less digits than its factorization.

381290721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18156711.

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 381290721 is about 19526.6669198816. Note that the first 3 decimals coincide. The cubic root of 381290721 is about 725.1347960224.

The spelling of 381290721 in words is "three hundred eighty-one million, two hundred ninety thousand, seven hundred twenty-one".