1986218421 has 16 divisors (see below), whose sum is σ = 2938014720. Its totient is φ = 1183364720.

The previous prime is 1986218413. The next prime is 1986218441. The reversal of 1986218421 is 1248126891.

It is a cyclic number.

It is not a de Polignac number, because 1986218421 - 2³ = 1986218413 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1986218441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 508125 + ... + 512018.

It is an arithmetic number, because the mean of its divisors is an integer number (183625920).

Almost surely, 2^1986218421 is an apocalyptic number.

1986218421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1986218421 is a deficient number, since it is larger than the sum of its proper divisors (951796299).

1986218421 is a wasteful number, since it uses less digits than its factorization.

1986218421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1020216.

The product of its digits is 55296, while the sum is 42.

The square root of 1986218421 is about 44567.0104561659. The cubic root of 1986218421 is about 1257.0204268827.

It can be divided in two parts, 19862 and 18421, that added together give a palindrome (38283).

The spelling of 1986218421 in words is "one billion, nine hundred eighty-six million, two hundred eighteen thousand, four hundred twenty-one".