2001991877 has 2 divisors, whose sum is σ = 2001991878. Its totient is φ = 2001991876.

The previous prime is 2001991847. The next prime is 2001991883. The reversal of 2001991877 is 7781991002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1023616036 + 978375841 = 31994^2 + 31279^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001991877 - 2¹⁰ = 2001990853 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001991847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000995938 + 1000995939.

It is an arithmetic number, because the mean of its divisors is an integer number (1000995939).

Almost surely, 2^2001991877 is an apocalyptic number.

It is an amenable number.

2001991877 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001991877 is an equidigital number, since it uses as much as digits as its factorization.

2001991877 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 63504, while the sum is 44.

The square root of 2001991877 is about 44743.6238697761. The cubic root of 2001991877 is about 1260.3391790754.

The spelling of 2001991877 in words is "two billion, one million, nine hundred ninety-one thousand, eight hundred seventy-seven".