381617661 has 4 divisors (see below), whose sum is σ = 508823552. Its totient is φ = 254411772.

The previous prime is 381617659. The next prime is 381617701. The reversal of 381617661 is 166716183.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 381617661 - 2¹ = 381617659 is a prime.

It is a super-2 number, since 2×381617661² = 291264078374221842, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (381619661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63602941 + ... + 63602946.

It is an arithmetic number, because the mean of its divisors is an integer number (127205888).

Almost surely, 2^381617661 is an apocalyptic number.

It is an amenable number.

381617661 is a deficient number, since it is larger than the sum of its proper divisors (127205891).

381617661 is a wasteful number, since it uses less digits than its factorization.

381617661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127205890.

The product of its digits is 36288, while the sum is 39.

The square root of 381617661 is about 19535.0367545086. The cubic root of 381617661 is about 725.3419938628.

The spelling of 381617661 in words is "three hundred eighty-one million, six hundred seventeen thousand, six hundred sixty-one".