21186614989 has 4 divisors (see below), whose sum is σ = 21194701020. Its totient is φ = 21178528960.

The previous prime is 21186614959. The next prime is 21186615017. The reversal of 21186614989 is 98941668112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17677829764 + 3508785225 = 132958^2 + 59235^2 .

It is a cyclic number.

It is not a de Polignac number, because 21186614989 - 2⁵ = 21186614957 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 (21186614959) 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 3 ways as a sum of consecutive naturals, for example, 4039084 + ... + 4044325.

It is an arithmetic number, because the mean of its divisors is an integer number (5298675255).

Almost surely, 2^21186614989 is an apocalyptic number.

It is an amenable number.

21186614989 is a deficient number, since it is larger than the sum of its proper divisors (8086031).

21186614989 is an equidigital number, since it uses as much as digits as its factorization.

21186614989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8086030.

The product of its digits is 1492992, while the sum is 55.

The spelling of 21186614989 in words is "twenty-one billion, one hundred eighty-six million, six hundred fourteen thousand, nine hundred eighty-nine".