1889523721 has 4 divisors (see below), whose sum is σ = 1895560852. Its totient is φ = 1883486592.

The previous prime is 1889523719. The next prime is 1889523743. The reversal of 1889523721 is 1273259881.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 238239225 + 1651284496 = 15435^2 + 40636^2 .

It is a cyclic number.

It is not a de Polignac number, because 1889523721 - 2¹ = 1889523719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1889523791) 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, 3018096 + ... + 3018721.

It is an arithmetic number, because the mean of its divisors is an integer number (473890213).

Almost surely, 2^1889523721 is an apocalyptic number.

It is an amenable number.

1889523721 is a deficient number, since it is larger than the sum of its proper divisors (6037131).

1889523721 is an equidigital number, since it uses as much as digits as its factorization.

1889523721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6037130.

The product of its digits is 241920, while the sum is 46.

The square root of 1889523721 is about 43468.6521645197. The cubic root of 1889523721 is about 1236.2817250459.

The spelling of 1889523721 in words is "one billion, eight hundred eighty-nine million, five hundred twenty-three thousand, seven hundred twenty-one".