919981 has 4 divisors (see below), whose sum is σ = 922432. Its totient is φ = 917532.

The previous prime is 919979. The next prime is 920011. The reversal of 919981 is 189919.

919981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 189919 = 179 ⋅1061.

It is a cyclic number.

It is not a de Polignac number, because 919981 - 2¹ = 919979 is a prime.

It is a super-2 number, since 2×919981² = 1692730080722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 919981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (919901) 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, 531 + ... + 1456.

It is an arithmetic number, because the mean of its divisors is an integer number (230608).

2⁹¹⁹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

919981 is a deficient number, since it is larger than the sum of its proper divisors (2451).

919981 is a wasteful number, since it uses less digits than its factorization.

919981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2450.

The product of its digits is 5832, while the sum is 37.

The square root of 919981 is about 959.1564001767. The cubic root of 919981 is about 97.2582130815.

The spelling of 919981 in words is "nine hundred nineteen thousand, nine hundred eighty-one".