381491551 has 8 divisors (see below), whose sum is σ = 437242400. Its totient is φ = 326053728.

The previous prime is 381491521. The next prime is 381491563. The reversal of 381491551 is 155194183.

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

It is not a de Polignac number, because 381491551 - 2¹⁷ = 381360479 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 381491551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (381491521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75636 + ... + 80521.

It is an arithmetic number, because the mean of its divisors is an integer number (54655300).

Almost surely, 2^381491551 is an apocalyptic number.

381491551 is a deficient number, since it is larger than the sum of its proper divisors (55750849).

381491551 is a wasteful number, since it uses less digits than its factorization.

381491551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156513.

The product of its digits is 21600, while the sum is 37.

The square root of 381491551 is about 19531.8086976091. The cubic root of 381491551 is about 725.2620858238.

The spelling of 381491551 in words is "three hundred eighty-one million, four hundred ninety-one thousand, five hundred fifty-one".