1561121 has 2 divisors, whose sum is σ = 1561122. Its totient is φ = 1561120.

The previous prime is 1561117. The next prime is 1561123. The reversal of 1561121 is 1211651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1132096 + 429025 = 1064^2 + 655^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561121 - 2² = 1561117 is a prime.

Together with 1561123, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1561121.

It is not a weakly prime, because it can be changed into another prime (1561123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780560 + 780561.

It is an arithmetic number, because the mean of its divisors is an integer number (780561).

2^1561121 is an apocalyptic number.

It is an amenable number.

1561121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561121 is an equidigital number, since it uses as much as digits as its factorization.

1561121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 60, while the sum is 17.

The square root of 1561121 is about 1249.4482782412. The cubic root of 1561121 is about 116.0055734540.

Adding to 1561121 its reverse (1211651), we get a palindrome (2772772).

It can be divided in two parts, 1561 and 121, that multiplied together give a palindrome (188881).

The spelling of 1561121 in words is "one million, five hundred sixty-one thousand, one hundred twenty-one".