1981959 has 8 divisors (see below), whose sum is σ = 3020160. Its totient is φ = 1132536.

The previous prime is 1981949. The next prime is 1981963. The reversal of 1981959 is 9591891.

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

It is not a de Polignac number, because 1981959 - 2¹¹ = 1979911 is a prime.

It is a super-2 number, since 2×1981959² = 7856322955362, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a zygodrome in base 2.

It is a self number, because there is not a number n which added to its sum of digits gives 1981959.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981919) 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, 47169 + ... + 47210.

It is an arithmetic number, because the mean of its divisors is an integer number (377520).

2^1981959 is an apocalyptic number.

1981959 is a deficient number, since it is larger than the sum of its proper divisors (1038201).

1981959 is an equidigital number, since it uses as much as digits as its factorization.

1981959 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94389.

The product of its digits is 29160, while the sum is 42.

The square root of 1981959 is about 1407.8206561917. The cubic root of 1981959 is about 125.6121228849.

The spelling of 1981959 in words is "one million, nine hundred eighty-one thousand, nine hundred fifty-nine".