7131645 has 20 divisors (see below), whose sum is σ = 12784860. Its totient is φ = 3803328.

The previous prime is 7131629. The next prime is 7131647. The reversal of 7131645 is 5461317.

7131645 is a `hidden beast` number, since 7 + 13 + 1 + 645 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 3956121 + 3175524 = 1989^2 + 1782^2 .

It is not a de Polignac number, because 7131645 - 2⁴ = 7131629 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

7131645 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7131647) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 8400 + ... + 9209.

It is an arithmetic number, because the mean of its divisors is an integer number (639243).

Almost surely, 2^7131645 is an apocalyptic number.

It is an amenable number.

7131645 is a deficient number, since it is larger than the sum of its proper divisors (5653215).

7131645 is a wasteful number, since it uses less digits than its factorization.

7131645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17626 (or 17617 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 7131645 is about 2670.5139954698. The cubic root of 7131645 is about 192.4848585381.

It can be divided in two parts, 7131 and 645, that added together give a 5-th power (7776 = 6⁵).

The spelling of 7131645 in words is "seven million, one hundred thirty-one thousand, six hundred forty-five".