1851482978421 has 4 divisors (see below), whose sum is σ = 2468643971232. Its totient is φ = 1234321985612.

The previous prime is 1851482978407. The next prime is 1851482978461. The reversal of 1851482978421 is 1248792841581.

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 not a de Polignac number, because 1851482978421 - 2¹³ = 1851482970229 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1851482978461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 308580496401 + ... + 308580496406.

It is an arithmetic number, because the mean of its divisors is an integer number (617160992808).

Almost surely, 2^{1851482978421} is an apocalyptic number.

It is an amenable number.

1851482978421 is a deficient number, since it is larger than the sum of its proper divisors (617160992811).

1851482978421 is an equidigital number, since it uses as much as digits as its factorization.

1851482978421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 617160992810.

The product of its digits is 10321920, while the sum is 60.

The spelling of 1851482978421 in words is "one trillion, eight hundred fifty-one billion, four hundred eighty-two million, nine hundred seventy-eight thousand, four hundred twenty-one".