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1919 = 19101

1919 has 4 divisors (see below), whose sum is σ = 2040. Its totient is φ = 1800.

The previous prime is 1913. The next prime is 1931. The reversal of 1919 is 9191.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1919 - 28 = 1663 is a prime.

It is a super-2 number, since 2×19192 = 7365122, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

1919 is an undulating number in base 10.

It is a plaindrome in base 8, base 12 and base 16.

It is a nialpdrome in base 7.

It is a self number, because there is not a number n which added to its sum of digits gives 1919.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1913) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32 + ... + 69.

It is an arithmetic number, because the mean of its divisors is an integer number (510).

21919 is an apocalyptic number.

1919 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1919 is a deficient number, since it is larger than the sum of its proper divisors (121).

1919 is a wasteful number, since it uses less digits than its factorization.

1919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120.

The product of its digits is 81, while the sum is 20.

The square root of 1919 is about 43.8063922276. The cubic root of 1919 is about 12.4267718487.

The spelling of 1919 in words is "one thousand, nine hundred nineteen".

Divisors: 1 19 101 1919