667601640 has 96 divisors (see below), whose sum is σ = 2200348800. Its totient is φ = 175512960.

The previous prime is 667601609. The next prime is 667601659. The reversal of 667601640 is 46106766.

667601640 is a `hidden beast` number, since 6 + 6 + 7 + 6 + 0 + 1 + 640 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 667601595 and 667601604.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12501 + ... + 38619.

It is an arithmetic number, because the mean of its divisors is an integer number (22920300).

Almost surely, 2^667601640 is an apocalyptic number.

667601640 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 667601640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1100174400).

667601640 is an abundant number, since it is smaller than the sum of its proper divisors (1532747160).

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

667601640 is a wasteful number, since it uses less digits than its factorization.

667601640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26207 (or 26200 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The square root of 667601640 is about 25837.9883117862. The cubic root of 667601640 is about 873.9886611889.

The spelling of 667601640 in words is "six hundred sixty-seven million, six hundred one thousand, six hundred forty".