7543981 has 4 divisors (see below), whose sum is σ = 7621852. Its totient is φ = 7466112.

The previous prime is 7543979. The next prime is 7544027. The reversal of 7543981 is 1893457.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1946025 + 5597956 = 1395^2 + 2366^2 .

It is a cyclic number.

It is not a de Polignac number, because 7543981 - 2¹ = 7543979 is a prime.

It is a super-2 number, since 2×7543981² = 113823298656722, which contains 22 as substring.

It is a Duffinian number.

7543981 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 7543981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7543901) 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 3 ways as a sum of consecutive naturals, for example, 38790 + ... + 38983.

It is an arithmetic number, because the mean of its divisors is an integer number (1905463).

Almost surely, 2^7543981 is an apocalyptic number.

It is an amenable number.

7543981 is a deficient number, since it is larger than the sum of its proper divisors (77871).

7543981 is an equidigital number, since it uses as much as digits as its factorization.

7543981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77870.

The product of its digits is 30240, while the sum is 37.

The square root of 7543981 is about 2746.6308452357. The cubic root of 7543981 is about 196.1252583344.

The spelling of 7543981 in words is "seven million, five hundred forty-three thousand, nine hundred eighty-one".