667880640 has 392 divisors, whose sum is σ = 2731800480. Its totient is φ = 152285184.

The previous prime is 667880639. The next prime is 667880651. The reversal of 667880640 is 46088766.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 1632756 + ... + 1633164.

Almost surely, 2^667880640 is an apocalyptic number.

667880640 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 667880640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1365900240).

667880640 is an abundant number, since it is smaller than the sum of its proper divisors (2063919840).

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

667880640 is an equidigital number, since it uses as much as digits as its factorization.

667880640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451 (or 426 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The square root of 667880640 is about 25843.3867749566. The cubic root of 667880640 is about 874.1103949002.

The spelling of 667880640 in words is "six hundred sixty-seven million, eight hundred eighty thousand, six hundred forty".