1851201081 has 8 divisors (see below), whose sum is σ = 2742520160. Its totient is φ = 1234134036.

The previous prime is 1851201073. The next prime is 1851201083. The reversal of 1851201081 is 1801021581.

It is not a de Polignac number, because 1851201081 - 2³ = 1851201073 is a prime.

It is a super-2 number, since 2×1851201081² = 6853890884591137122, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 68563003 = 1851201081 / (1 + 8 + 5 + 1 + 2 + 0 + 1 + 0 + 8 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1851201083) 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 in 7 ways as a sum of consecutive naturals, for example, 34281475 + ... + 34281528.

It is an arithmetic number, because the mean of its divisors is an integer number (342815020).

Almost surely, 2^1851201081 is an apocalyptic number.

It is an amenable number.

1851201081 is a deficient number, since it is larger than the sum of its proper divisors (891319079).

1851201081 is an equidigital number, since it uses as much as digits as its factorization.

1851201081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68563012 (or 68563006 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 27.

The square root of 1851201081 is about 43025.5863527739. The cubic root of 1851201081 is about 1227.8666350744.

The spelling of 1851201081 in words is "one billion, eight hundred fifty-one million, two hundred one thousand, eighty-one".