501981 has 8 divisors (see below), whose sum is σ = 674400. Its totient is φ = 332112.

The previous prime is 501971. The next prime is 501997. The reversal of 501981 is 189105.

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

It is not a de Polignac number, because 501981 - 2¹⁰ = 500957 is a prime.

It is a super-2 number, since 2×501981² = 503969848722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon 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 501981.

It is not an unprimeable number, because it can be changed into a prime (501911) 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, 115 + ... + 1008.

It is an arithmetic number, because the mean of its divisors is an integer number (84300).

2⁵⁰¹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

501981 is a deficient number, since it is larger than the sum of its proper divisors (172419).

501981 is a wasteful number, since it uses less digits than its factorization.

501981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1275.

The product of its (nonzero) digits is 360, while the sum is 24.

The square root of 501981 is about 708.5061749907. The cubic root of 501981 is about 79.4747358510.

The spelling of 501981 in words is "five hundred one thousand, nine hundred eighty-one".