1861854221 has 2 divisors, whose sum is σ = 1861854222. Its totient is φ = 1861854220.

The previous prime is 1861854217. The next prime is 1861854277. The reversal of 1861854221 is 1224581681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 969637321 + 892216900 = 31139^2 + 29870^2 .

It is a cyclic number.

It is not a de Polignac number, because 1861854221 - 2² = 1861854217 is a prime.

It is a super-2 number, since 2×1861854221² = 6933002280511033682, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1861853221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 930927110 + 930927111.

It is an arithmetic number, because the mean of its divisors is an integer number (930927111).

Almost surely, 2^1861854221 is an apocalyptic number.

It is an amenable number.

1861854221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861854221 is an equidigital number, since it uses as much as digits as its factorization.

1861854221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30720, while the sum is 38.

The square root of 1861854221 is about 43149.2088108229. The cubic root of 1861854221 is about 1230.2174733894.

The spelling of 1861854221 in words is "one billion, eight hundred sixty-one million, eight hundred fifty-four thousand, two hundred twenty-one".