42001999891 has 2 divisors, whose sum is σ = 42001999892. Its totient is φ = 42001999890.

The previous prime is 42001999883. The next prime is 42001999937. The reversal of 42001999891 is 19899910024.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 42001999891 - 2³ = 42001999883 is a prime.

It is not a weakly prime, because it can be changed into another prime (42001909891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21000999945 + 21000999946.

It is an arithmetic number, because the mean of its divisors is an integer number (21000999946).

Almost surely, 2^42001999891 is an apocalyptic number.

42001999891 is a deficient number, since it is larger than the sum of its proper divisors (1).

42001999891 is an equidigital number, since it uses as much as digits as its factorization.

42001999891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 419904, while the sum is 52.

The spelling of 42001999891 in words is "forty-two billion, one million, nine hundred ninety-nine thousand, eight hundred ninety-one".