6661551 has 8 divisors (see below), whose sum is σ = 9565360. Its totient is φ = 4099392.

The previous prime is 6661549. The next prime is 6661553. The reversal of 6661551 is 1551666.

It is an interprime number because it is at equal distance from previous prime (6661549) and next prime (6661553).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 6661551 - 2¹ = 6661549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6661553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85366 + ... + 85443.

It is an arithmetic number, because the mean of its divisors is an integer number (1195670).

Almost surely, 2^6661551 is an apocalyptic number.

6661551 is a deficient number, since it is larger than the sum of its proper divisors (2903809).

6661551 is a wasteful number, since it uses less digits than its factorization.

6661551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170825.

The product of its digits is 5400, while the sum is 30.

The square root of 6661551 is about 2580.9980627656. The cubic root of 6661551 is about 188.1590531910.

It can be divided in two parts, 66615 and 51, that added together give a palindrome (66666).

The spelling of 6661551 in words is "six million, six hundred sixty-one thousand, five hundred fifty-one".