1891891983 has 4 divisors (see below), whose sum is σ = 2522522648. Its totient is φ = 1261261320.

The previous prime is 1891891951. The next prime is 1891891993. The reversal of 1891891983 is 3891981981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3891981981 = 3 ⋅1297327327.

It is not a de Polignac number, because 1891891983 - 2⁵ = 1891891951 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1891891993) 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, 315315328 + ... + 315315333.

It is an arithmetic number, because the mean of its divisors is an integer number (630630662).

Almost surely, 2^1891891983 is an apocalyptic number.

1891891983 is a deficient number, since it is larger than the sum of its proper divisors (630630665).

1891891983 is an equidigital number, since it uses as much as digits as its factorization.

1891891983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630630664.

The product of its digits is 1119744, while the sum is 57.

The square root of 1891891983 is about 43495.8846674027. The cubic root of 1891891983 is about 1236.7980132923.

The spelling of 1891891983 in words is "one billion, eight hundred ninety-one million, eight hundred ninety-one thousand, nine hundred eighty-three".