66405187589 has 4 divisors (see below), whose sum is σ = 71513278956. Its totient is φ = 61297096224.

The previous prime is 66405187573. The next prime is 66405187609. The reversal of 66405187589 is 98578150466.

It is a happy number.

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 18839758564 + 47565429025 = 137258^2 + 218095^2 .

It is not a de Polignac number, because 66405187589 - 2⁴ = 66405187573 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 (66405189589) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2554045664 + ... + 2554045689.

It is an arithmetic number, because the mean of its divisors is an integer number (17878319739).

Almost surely, 2^66405187589 is an apocalyptic number.

It is an amenable number.

66405187589 is a deficient number, since it is larger than the sum of its proper divisors (5108091367).

66405187589 is a wasteful number, since it uses less digits than its factorization.

66405187589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5108091366.

The product of its (nonzero) digits is 14515200, while the sum is 59.

The spelling of 66405187589 in words is "sixty-six billion, four hundred five million, one hundred eighty-seven thousand, five hundred eighty-nine".