1321851878 has 4 divisors (see below), whose sum is σ = 1982777820. Its totient is φ = 660925938.

The previous prime is 1321851877. The next prime is 1321851889. The reversal of 1321851878 is 8781581231.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8781581231 = 293 ⋅29971267.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321851877) 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 as a sum of consecutive naturals, namely, 330462968 + ... + 330462971.

It is an arithmetic number, because the mean of its divisors is an integer number (495694455).

Almost surely, 2^1321851878 is an apocalyptic number.

1321851878 is a deficient number, since it is larger than the sum of its proper divisors (660925942).

1321851878 is an equidigital number, since it uses as much as digits as its factorization.

1321851878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660925941.

The product of its digits is 107520, while the sum is 44.

The square root of 1321851878 is about 36357.2809489379. The cubic root of 1321851878 is about 1097.4740603005.

The spelling of 1321851878 in words is "one billion, three hundred twenty-one million, eight hundred fifty-one thousand, eight hundred seventy-eight".