7123561 has 9 divisors (see below), whose sum is σ = 7615749.
Its totient is φ = 6661824.
The previous prime is 7123549. The next prime is 7123579. The reversal of 7123561 is 1653217.
The square root of 7123561 is 2669.
It is a perfect power (a square), and thus also a powerful number.
It can be written as a sum of positive squares in 4 ways, for example, as 47961 + 7075600 = 219^2 + 2660^2
It is not a de Polignac number, because 7123561 - 215 = 7090793 is a prime.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (7123511) by changing a digit.
It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 45295 + ... + 45451.
Almost surely, 27123561 is an apocalyptic number.
7123561 is the 2669-th square number.
7123561 is the 1335-th centered octagonal number.
It is an amenable number.
7123561 is a deficient number, since it is larger than the sum of its proper divisors (492188).
7123561 is an equidigital number, since it uses as much as digits as its factorization.
7123561 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 348 (or 174 counting only the distinct ones).
The product of its digits is 1260, while the sum is 25.
The cubic root of 7123561 is about 192.4121013217.
Multiplying 7123561 by its sum of digits (25), we get a square (178089025 = 133452).
Adding to 7123561 its reverse (1653217), we get a palindrome (8776778).
It can be divided in two parts, 71 and 23561, that added together give a palindrome (23632).
The spelling of 7123561 in words is "seven million, one hundred twenty-three thousand, five hundred sixty-one".