1561541 has 2 divisors, whose sum is σ = 1561542. Its totient is φ = 1561540.

The previous prime is 1561537. The next prime is 1561559. The reversal of 1561541 is 1451651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1552516 + 9025 = 1246^2 + 95^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561541 - 2² = 1561537 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561741) 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 as a sum of consecutive naturals, namely, 780770 + 780771.

It is an arithmetic number, because the mean of its divisors is an integer number (780771).

2^1561541 is an apocalyptic number.

It is an amenable number.

1561541 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561541 is an equidigital number, since it uses as much as digits as its factorization.

1561541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 600, while the sum is 23.

The square root of 1561541 is about 1249.6163411223. The cubic root of 1561541 is about 116.0159758021.

The spelling of 1561541 in words is "one million, five hundred sixty-one thousand, five hundred forty-one".