1918451861 has 2 divisors, whose sum is σ = 1918451862. Its totient is φ = 1918451860.

The previous prime is 1918451849. The next prime is 1918451881. The reversal of 1918451861 is 1681548191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1716527761 + 201924100 = 41431^2 + 14210^2 .

It is a cyclic number.

It is not a de Polignac number, because 1918451861 - 2⁶ = 1918451797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1918451881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 959225930 + 959225931.

It is an arithmetic number, because the mean of its divisors is an integer number (959225931).

Almost surely, 2^1918451861 is an apocalyptic number.

It is an amenable number.

1918451861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1918451861 is an equidigital number, since it uses as much as digits as its factorization.

1918451861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69120, while the sum is 44.

The square root of 1918451861 is about 43800.1353993341. The cubic root of 1918451861 is about 1242.5588550675.

The spelling of 1918451861 in words is "one billion, nine hundred eighteen million, four hundred fifty-one thousand, eight hundred sixty-one".