1919981 has 4 divisors (see below), whose sum is σ = 2194272. Its totient is φ = 1645692.

The previous prime is 1919959. The next prime is 1919987. The reversal of 1919981 is 1899191.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 1919981 - 2⁶ = 1919917 is a prime.

It is a super-2 number, since 2×1919981² = 7372654080722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1919987) 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, 137135 + ... + 137148.

It is an arithmetic number, because the mean of its divisors is an integer number (548568).

2^1919981 is an apocalyptic number.

It is an amenable number.

1919981 is a deficient number, since it is larger than the sum of its proper divisors (274291).

1919981 is an equidigital number, since it uses as much as digits as its factorization.

1919981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274290.

The product of its digits is 5832, while the sum is 38.

The square root of 1919981 is about 1385.6337900037. The cubic root of 1919981 is about 124.2888902547.

The spelling of 1919981 in words is "one million, nine hundred nineteen thousand, nine hundred eighty-one".