1666400 has 36 divisors (see below), whose sum is σ = 4070052. Its totient is φ = 666240.

The previous prime is 1666397. The next prime is 1666403. The reversal of 1666400 is 46661.

It is an interprime number because it is at equal distance from previous prime (1666397) and next prime (1666403).

It is a super-4 number, since 4×1666400⁴ (a number of 26 digits) contains 4444 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666403) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 242 + ... + 1841.

It is an arithmetic number, because the mean of its divisors is an integer number (113057).

2^1666400 is an apocalyptic number.

1666400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1666400 is an abundant number, since it is smaller than the sum of its proper divisors (2403652).

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

1666400 is a wasteful number, since it uses less digits than its factorization.

1666400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2103 (or 2090 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 1666400 is about 1290.8911650484. The cubic root of 1666400 is about 118.5567864465.

The spelling of 1666400 in words is "one million, six hundred sixty-six thousand, four hundred".