351981 has 24 divisors (see below), whose sum is σ = 600704. Its totient is φ = 194400.

The previous prime is 351971. The next prime is 351991. The reversal of 351981 is 189153.

It is an interprime number because it is at equal distance from previous prime (351971) and next prime (351991).

It is not a de Polignac number, because 351981 - 2⁹ = 351469 is a prime.

It is a super-2 number, since 2×351981² = 247781248722, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 351981.

It is not an unprimeable number, because it can be changed into a prime (351931) 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 23 ways as a sum of consecutive naturals, for example, 2256 + ... + 2406.

2³⁵¹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

351981 is a deficient number, since it is larger than the sum of its proper divisors (248723).

351981 is a wasteful number, since it uses less digits than its factorization.

351981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201 (or 198 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 351981 is about 593.2798665048. The cubic root of 351981 is about 70.6056962932.

It can be divided in two parts, 3519 and 81, that added together give a square (3600 = 60²).

The spelling of 351981 in words is "three hundred fifty-one thousand, nine hundred eighty-one".