66426989 has 4 divisors (see below), whose sum is σ = 66514140. Its totient is φ = 66339840.

The previous prime is 66426953. The next prime is 66427037. The reversal of 66426989 is 98962466.

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 26522500 + 39904489 = 5150^2 + 6317^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66426989 is a prime.

It is a super-2 number, since 2×66426989² = 8825089735212242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66423989) 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, 42422 + ... + 43959.

It is an arithmetic number, because the mean of its divisors is an integer number (16628535).

Almost surely, 2^66426989 is an apocalyptic number.

It is an amenable number.

66426989 is a deficient number, since it is larger than the sum of its proper divisors (87151).

66426989 is an equidigital number, since it uses as much as digits as its factorization.

66426989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87150.

The product of its digits is 1119744, while the sum is 50.

The square root of 66426989 is about 8150.2753941201. The cubic root of 66426989 is about 404.9936268875.

It can be divided in two parts, 6642 and 6989, that added together give a palindrome (13631).

The spelling of 66426989 in words is "sixty-six million, four hundred twenty-six thousand, nine hundred eighty-nine".