1201561 has 4 divisors (see below), whose sum is σ = 1204324. Its totient is φ = 1198800.

The previous prime is 1201559. The next prime is 1201567. The reversal of 1201561 is 1651021.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1651021 = 79 ⋅20899.

It can be written as a sum of positive squares in 2 ways, for example, as 648025 + 553536 = 805^2 + 744^2 .

It is a cyclic number.

It is not a de Polignac number, because 1201561 - 2¹ = 1201559 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (1201567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 570 + ... + 1651.

It is an arithmetic number, because the mean of its divisors is an integer number (301081).

2^1201561 is an apocalyptic number.

It is an amenable number.

1201561 is a deficient number, since it is larger than the sum of its proper divisors (2763).

1201561 is an equidigital number, since it uses as much as digits as its factorization.

1201561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2762.

The product of its (nonzero) digits is 60, while the sum is 16.

The square root of 1201561 is about 1096.1573792116. The cubic root of 1201561 is about 106.3119150090.

Adding to 1201561 its reverse (1651021), we get a palindrome (2852582).

It can be divided in two parts, 120 and 1561, that added together give a square (1681 = 41²).

The spelling of 1201561 in words is "one million, two hundred one thousand, five hundred sixty-one".