1891663141 has 2 divisors, whose sum is σ = 1891663142. Its totient is φ = 1891663140.

The previous prime is 1891663139. The next prime is 1891663157. The reversal of 1891663141 is 1413661981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1832696100 + 58967041 = 42810^2 + 7679^2 .

It is a cyclic number.

It is not a de Polignac number, because 1891663141 - 2¹ = 1891663139 is a prime.

Together with 1891663139, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 1891663094 and 1891663103.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1891463141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 945831570 + 945831571.

It is an arithmetic number, because the mean of its divisors is an integer number (945831571).

Almost surely, 2^1891663141 is an apocalyptic number.

It is an amenable number.

1891663141 is a deficient number, since it is larger than the sum of its proper divisors (1).

1891663141 is an equidigital number, since it uses as much as digits as its factorization.

1891663141 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104, while the sum is 40.

The square root of 1891663141 is about 43493.2539711620. The cubic root of 1891663141 is about 1236.7481438590.

The spelling of 1891663141 in words is "one billion, eight hundred ninety-one million, six hundred sixty-three thousand, one hundred forty-one".