1851555049 has 4 divisors (see below), whose sum is σ = 1851834960. Its totient is φ = 1851275140.

The previous prime is 1851555037. The next prime is 1851555091. The reversal of 1851555049 is 9405551581.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1851555049 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1851554996 and 1851555014.

It is not an unprimeable number, because it can be changed into a prime (1851555649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129787 + ... + 143344.

It is an arithmetic number, because the mean of its divisors is an integer number (462958740).

Almost surely, 2^1851555049 is an apocalyptic number.

It is an amenable number.

1851555049 is a deficient number, since it is larger than the sum of its proper divisors (279911).

1851555049 is an equidigital number, since it uses as much as digits as its factorization.

1851555049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279910.

The product of its (nonzero) digits is 180000, while the sum is 43.

The square root of 1851555049 is about 43029.6996154981. The cubic root of 1851555049 is about 1227.9448901782.

The spelling of 1851555049 in words is "one billion, eight hundred fifty-one million, five hundred fifty-five thousand, forty-nine".