1891277849 has 2 divisors, whose sum is σ = 1891277850. Its totient is φ = 1891277848.

The previous prime is 1891277827. The next prime is 1891277881. The reversal of 1891277849 is 9487721981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1252806025 + 638471824 = 35395^2 + 25268^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1891277849 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1891277794 and 1891277803.

It is not a weakly prime, because it can be changed into another prime (1891277819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 945638924 + 945638925.

It is an arithmetic number, because the mean of its divisors is an integer number (945638925).

Almost surely, 2^1891277849 is an apocalyptic number.

It is an amenable number.

1891277849 is a deficient number, since it is larger than the sum of its proper divisors (1).

1891277849 is an equidigital number, since it uses as much as digits as its factorization.

1891277849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2032128, while the sum is 56.

The square root of 1891277849 is about 43488.8244150149. The cubic root of 1891277849 is about 1236.6641716283.

The spelling of 1891277849 in words is "one billion, eight hundred ninety-one million, two hundred seventy-seven thousand, eight hundred forty-nine".