1891002002 has 18 divisors (see below), whose sum is σ = 2875116447. Its totient is φ = 932801664.

The previous prime is 1891001977. The next prime is 1891002019. The reversal of 1891002002 is 2002001981.

It can be written as a sum of positive squares in 5 ways, for example, as 65918161 + 1825083841 = 8119^2 + 42721^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=30749.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 5965148 + ... + 5965464.

Almost surely, 2^1891002002 is an apocalyptic number.

1891002002 is a deficient number, since it is larger than the sum of its proper divisors (984114445).

1891002002 is an frugal number, since it uses more digits than its factorization.

1891002002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 830 (or 416 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 1891002002 is about 43485.6528294103. The cubic root of 1891002002 is about 1236.6040453159.

Multiplying 1891002002 by its product of nonzero digits (288), we get a square (544608576576 = 737976²).

Adding to 1891002002 its reverse (2002001981), we get a palindrome (3893003983).

The spelling of 1891002002 in words is "one billion, eight hundred ninety-one million, two thousand, two".