1861278493 has 12 divisors (see below), whose sum is σ = 1930275360. Its totient is φ = 1794672656.

The previous prime is 1861278479. The next prime is 1861278511. The reversal of 1861278493 is 3948721681.

It is a de Polignac number, because none of the positive numbers 2^k-1861278493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1861278413) 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 11 ways as a sum of consecutive naturals, for example, 1148838 + ... + 1150456.

It is an arithmetic number, because the mean of its divisors is an integer number (160856280).

Almost surely, 2^1861278493 is an apocalyptic number.

It is an amenable number.

1861278493 is a deficient number, since it is larger than the sum of its proper divisors (68996867).

1861278493 is a wasteful number, since it uses less digits than its factorization.

1861278493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3044 (or 3015 counting only the distinct ones).

The product of its digits is 580608, while the sum is 49.

The square root of 1861278493 is about 43142.5369328230. The cubic root of 1861278493 is about 1230.0906565035.

The spelling of 1861278493 in words is "one billion, eight hundred sixty-one million, two hundred seventy-eight thousand, four hundred ninety-three".