667221888 has 128 divisors (see below), whose sum is σ = 1838154240. Its totient is φ = 214272000.

The previous prime is 667221887. The next prime is 667221901. The reversal of 667221888 is 888122766.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (48).

Its product of digits (516096) is a multiple of the sum of its prime divisors (504).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667221887) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2145253 + ... + 2145563.

It is an arithmetic number, because the mean of its divisors is an integer number (14360580).

Almost surely, 2^667221888 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 667221888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (919077120).

667221888 is an abundant number, since it is smaller than the sum of its proper divisors (1170932352).

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

667221888 is a wasteful number, since it uses less digits than its factorization.

667221888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516 (or 504 counting only the distinct ones).

The product of its digits is 516096, while the sum is 48.

The square root of 667221888 is about 25830.6385519212. The cubic root of 667221888 is about 873.8229126978.

The spelling of 667221888 in words is "six hundred sixty-seven million, two hundred twenty-one thousand, eight hundred eighty-eight".