667917720 has 48 divisors (see below), whose sum is σ = 2170733760. Its totient is φ = 178111296.

The previous prime is 667917689. The next prime is 667917727. The reversal of 667917720 is 27719766.

It is a super-2 number, since 2×667917720² = 892228161379996800, which contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667917727) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 927304 + ... + 928023.

It is an arithmetic number, because the mean of its divisors is an integer number (45223620).

Almost surely, 2^667917720 is an apocalyptic number.

667917720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

667917720 is an abundant number, since it is smaller than the sum of its proper divisors (1502816040).

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

667917720 is a wasteful number, since it uses less digits than its factorization.

667917720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1855344 (or 1855337 counting only the distinct ones).

The product of its (nonzero) digits is 222264, while the sum is 45.

The square root of 667917720 is about 25844.1041632323. The cubic root of 667917720 is about 874.1265711507.

The spelling of 667917720 in words is "six hundred sixty-seven million, nine hundred seventeen thousand, seven hundred twenty".