6661655 has 40 divisors (see below), whose sum is σ = 10822560. Its totient is φ = 3833280.

The previous prime is 6661649. The next prime is 6661661. The reversal of 6661655 is 5561666.

It is an interprime number because it is at equal distance from previous prime (6661649) and next prime (6661661).

It is not a de Polignac number, because 6661655 - 2¹⁸ = 6399511 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

Its product of digits (32400) is a multiple of the sum of its prime divisors (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 512429 + ... + 512441.

It is an arithmetic number, because the mean of its divisors is an integer number (270564).

Almost surely, 2^6661655 is an apocalyptic number.

6661655 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

6661655 is a deficient number, since it is larger than the sum of its proper divisors (4160905).

6661655 is an equidigital number, since it uses as much as digits as its factorization.

6661655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69 (or 36 counting only the distinct ones).

The product of its digits is 32400, while the sum is 35.

The square root of 6661655 is about 2581.0182099319. The cubic root of 6661655 is about 188.1600323644.

The spelling of 6661655 in words is "six million, six hundred sixty-one thousand, six hundred fifty-five".