667921840 has 160 divisors (see below), whose sum is σ = 1739460096. Its totient is φ = 237219840.

The previous prime is 667921819. The next prime is 667921867. The reversal of 667921840 is 48129766.

It is a super-2 number, since 2×667921840² = 892239168697971200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4097599 + ... + 4097761.

Almost surely, 2^667921840 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 667921840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (869730048).

667921840 is an abundant number, since it is smaller than the sum of its proper divisors (1071538256).

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

667921840 is a wasteful number, since it uses less digits than its factorization.

667921840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347 (or 341 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 667921840 is about 25844.1838718115. The cubic root of 667921840 is about 874.1283684749.

The spelling of 667921840 in words is "six hundred sixty-seven million, nine hundred twenty-one thousand, eight hundred forty".