1891002001 has 16 divisors (see below), whose sum is σ = 2221648128. Its totient is φ = 1576108800.

The previous prime is 1891001977. The next prime is 1891002019. The reversal of 1891002001 is 1002001981.

It is not a de Polignac number, because 1891002001 - 2⁵ = 1891001969 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1891002601) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10221 + ... + 62341.

It is an arithmetic number, because the mean of its divisors is an integer number (138853008).

Almost surely, 2^1891002001 is an apocalyptic number.

It is an amenable number.

1891002001 is a deficient number, since it is larger than the sum of its proper divisors (330646127).

1891002001 is an equidigital number, since it uses as much as digits as its factorization.

1891002001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52272.

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 1891002001 is about 43485.6528179123. The cubic root of 1891002001 is about 1236.6040450979.

Adding to 1891002001 its reverse (1002001981), we get a palindrome (2893003982).

The spelling of 1891002001 in words is "one billion, eight hundred ninety-one million, two thousand, one".