6661545 has 32 divisors (see below), whose sum is σ = 11888640. Its totient is φ = 3157440.

The previous prime is 6661511. The next prime is 6661547. The reversal of 6661545 is 5451666.

It is not a de Polignac number, because 6661545 - 2¹² = 6657449 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

6661545 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6661547) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7326 + ... + 8184.

It is an arithmetic number, because the mean of its divisors is an integer number (371520).

Almost surely, 2^6661545 is an apocalyptic number.

It is an amenable number.

6661545 is a deficient number, since it is larger than the sum of its proper divisors (5227095).

6661545 is a wasteful number, since it uses less digits than its factorization.

6661545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 925.

The product of its digits is 21600, while the sum is 33.

The square root of 6661545 is about 2580.9969004243. The cubic root of 6661545 is about 188.1589966999.

It can be divided in two parts, 666 and 1545, that added together give a triangular number (2211 = T₆₆).

The spelling of 6661545 in words is "six million, six hundred sixty-one thousand, five hundred forty-five".