66889998 has 72 divisors (see below), whose sum is σ = 169926120. Its totient is φ = 18960480.

The previous prime is 66889993. The next prime is 66890017. The reversal of 66889998 is 89998866.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66889993) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 159433 + ... + 159851.

It is an arithmetic number, because the mean of its divisors is an integer number (2360085).

Almost surely, 2^66889998 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66889998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84963060).

66889998 is an abundant number, since it is smaller than the sum of its proper divisors (103036122).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66889998 is a wasteful number, since it uses less digits than its factorization.

66889998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 622 (or 612 counting only the distinct ones).

The product of its digits is 13436928, while the sum is 63.

The square root of 66889998 is about 8178.6305699671. The cubic root of 66889998 is about 405.9324104687.

The spelling of 66889998 in words is "sixty-six million, eight hundred eighty-nine thousand, nine hundred ninety-eight".