6661400 has 48 divisors (see below), whose sum is σ = 16312200. Its totient is φ = 2522880.

The previous prime is 6661379. The next prime is 6661409. The reversal of 6661400 is 41666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6661409) 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, 2924 + ... + 4676.

Almost surely, 2^6661400 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 6661400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8156100).

6661400 is an abundant number, since it is smaller than the sum of its proper divisors (9650800).

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

6661400 is a wasteful number, since it uses less digits than its factorization.

6661400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1788 (or 1779 counting only the distinct ones).

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

The square root of 6661400 is about 2580.9688103501. The cubic root of 6661400 is about 188.1576314885.

The spelling of 6661400 in words is "six million, six hundred sixty-one thousand, four hundred".