666998880 has 96 divisors (see below), whose sum is σ = 2104649568. Its totient is φ = 177561600.

The previous prime is 666998879. The next prime is 666998881. The reversal of 666998880 is 88899666.

It is an interprime number because it is at equal distance from previous prime (666998879) and next prime (666998881).

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666998881) 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, 489400 + ... + 490760.

It is an arithmetic number, because the mean of its divisors is an integer number (21923433).

Almost surely, 2^666998880 is an apocalyptic number.

666998880 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 666998880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1052324784).

666998880 is an abundant number, since it is smaller than the sum of its proper divisors (1437650688).

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

666998880 is a wasteful number, since it uses less digits than its factorization.

666998880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2400 (or 2392 counting only the distinct ones).

The product of its (nonzero) digits is 8957952, while the sum is 60.

The square root of 666998880 is about 25826.3214569942. The cubic root of 666998880 is about 873.7255481787.

The spelling of 666998880 in words is "six hundred sixty-six million, nine hundred ninety-eight thousand, eight hundred eighty".