7125781 has 8 divisors (see below), whose sum is σ = 7731864. Its totient is φ = 6528000.

The previous prime is 7125761. The next prime is 7125787. The reversal of 7125781 is 1875217.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 18225 + 7107556 = 135^2 + 2666^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 7125781 - 2⁹ = 7125269 is a prime.

It is a super-2 number, since 2×7125781² = 101553509719922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7125787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 220 + ... + 3781.

It is an arithmetic number, because the mean of its divisors is an integer number (966483).

Almost surely, 2^7125781 is an apocalyptic number.

It is an amenable number.

7125781 is a deficient number, since it is larger than the sum of its proper divisors (606083).

7125781 is a wasteful number, since it uses less digits than its factorization.

7125781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4151.

The product of its digits is 3920, while the sum is 31.

The square root of 7125781 is about 2669.4158537028. The cubic root of 7125781 is about 192.4320871359.

It can be divided in two parts, 71 and 25781, that added together give a palindrome (25852).

The spelling of 7125781 in words is "seven million, one hundred twenty-five thousand, seven hundred eighty-one".