1005381 has 18 divisors (see below), whose sum is σ = 1574898. Its totient is φ = 617760.

The previous prime is 1005373. The next prime is 1005391. The reversal of 1005381 is 1835001.

1005381 = 184² + 185² + ... + 209².

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 25281 + 980100 = 159^2 + 990^2 .

It is not a de Polignac number, because 1005381 - 2³ = 1005373 is a prime.

It is a super-2 number, since 2×1005381² = 2021581910322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1005331) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1191 + ... + 1851.

2^1005381 is an apocalyptic number.

It is an amenable number.

1005381 is a deficient number, since it is larger than the sum of its proper divisors (569517).

1005381 is a wasteful number, since it uses less digits than its factorization.

1005381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 693 (or 677 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 1005381 is about 1002.6868903102. The cubic root of 1005381 is about 100.1790459010.

The spelling of 1005381 in words is "one million, five thousand, three hundred eighty-one".