66215708989 has 4 divisors (see below), whose sum is σ = 66216806656. Its totient is φ = 66214611324.

The previous prime is 66215708969. The next prime is 66215709017. The reversal of 66215708989 is 98980751266.

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 66215708989 - 2³³ = 57625774397 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 (66215708959) 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, 452739 + ... + 580864.

It is an arithmetic number, because the mean of its divisors is an integer number (16554201664).

Almost surely, 2^66215708989 is an apocalyptic number.

It is an amenable number.

66215708989 is a deficient number, since it is larger than the sum of its proper divisors (1097667).

66215708989 is a wasteful number, since it uses less digits than its factorization.

66215708989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1097666.

The product of its (nonzero) digits is 13063680, while the sum is 61.

The spelling of 66215708989 in words is "sixty-six billion, two hundred fifteen million, seven hundred eight thousand, nine hundred eighty-nine".