6631381 has 4 divisors (see below), whose sum is σ = 6793164. Its totient is φ = 6469600.

The previous prime is 6631379. The next prime is 6631409. The reversal of 6631381 is 1831366.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1831366 = 2 ⋅915683.

It can be written as a sum of positive squares in 2 ways, for example, as 828100 + 5803281 = 910^2 + 2409^2 .

It is a cyclic number.

It is not a de Polignac number, because 6631381 - 2¹ = 6631379 is a prime.

It is a super-2 number, since 2×6631381² = 87950427934322, which contains 22 as substring.

It is a Duffinian number.

6631381 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6631321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80830 + ... + 80911.

It is an arithmetic number, because the mean of its divisors is an integer number (1698291).

Almost surely, 2^6631381 is an apocalyptic number.

It is an amenable number.

6631381 is a deficient number, since it is larger than the sum of its proper divisors (161783).

6631381 is a wasteful number, since it uses less digits than its factorization.

6631381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161782.

The product of its digits is 2592, while the sum is 28.

The square root of 6631381 is about 2575.1467919325. The cubic root of 6631381 is about 187.8745673794.

The spelling of 6631381 in words is "six million, six hundred thirty-one thousand, three hundred eighty-one".