1851459649 has 4 divisors (see below), whose sum is σ = 1993879636. Its totient is φ = 1709039664.

The previous prime is 1851459629. The next prime is 1851459671. The reversal of 1851459649 is 9469541581.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9469541581 = 1607 ⋅5892683.

It can be written as a sum of positive squares in 2 ways, for example, as 440706049 + 1410753600 = 20993^2 + 37560^2 .

It is a cyclic number.

It is not a de Polignac number, because 1851459649 - 2⁷ = 1851459521 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1851459596 and 1851459605.

It is not an unprimeable number, because it can be changed into a prime (1851459619) 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 in 3 ways as a sum of consecutive naturals, for example, 71209974 + ... + 71209999.

It is an arithmetic number, because the mean of its divisors is an integer number (498469909).

Almost surely, 2^1851459649 is an apocalyptic number.

It is an amenable number.

1851459649 is a deficient number, since it is larger than the sum of its proper divisors (142419987).

1851459649 is a wasteful number, since it uses less digits than its factorization.

1851459649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142419986.

The product of its digits is 1555200, while the sum is 52.

The square root of 1851459649 is about 43028.5910645468. The cubic root of 1851459649 is about 1227.9238001662.

The spelling of 1851459649 in words is "one billion, eight hundred fifty-one million, four hundred fifty-nine thousand, six hundred forty-nine".