667218420 has 144 divisors (see below), whose sum is σ = 2262012480. Its totient is φ = 157785600.

The previous prime is 667218413. The next prime is 667218449. The reversal of 667218420 is 24812766.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 77071 + ... + 85289.

It is an arithmetic number, because the mean of its divisors is an integer number (15708420).

Almost surely, 2^667218420 is an apocalyptic number.

667218420 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 667218420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1131006240).

667218420 is an abundant number, since it is smaller than the sum of its proper divisors (1594794060).

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

667218420 is a wasteful number, since it uses less digits than its factorization.

667218420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8286 (or 8281 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The square root of 667218420 is about 25830.5714222508. The cubic root of 667218420 is about 873.8213987471.

The spelling of 667218420 in words is "six hundred sixty-seven million, two hundred eighteen thousand, four hundred twenty".