1561577 has 2 divisors, whose sum is σ = 1561578. Its totient is φ = 1561576.

The previous prime is 1561559. The next prime is 1561579. The reversal of 1561577 is 7751651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1104601 + 456976 = 1051^2 + 676^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561577 - 2¹² = 1557481 is a prime.

Together with 1561579, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1561579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780788 + 780789.

It is an arithmetic number, because the mean of its divisors is an integer number (780789).

2^1561577 is an apocalyptic number.

It is an amenable number.

1561577 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561577 is an equidigital number, since it uses as much as digits as its factorization.

1561577 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7350, while the sum is 32.

The square root of 1561577 is about 1249.6307454604. The cubic root of 1561577 is about 116.0168673451.

The spelling of 1561577 in words is "one million, five hundred sixty-one thousand, five hundred seventy-seven".