1561941461 has 2 divisors, whose sum is σ = 1561941462. Its totient is φ = 1561941460.

The previous prime is 1561941457. The next prime is 1561941509. The reversal of 1561941461 is 1641491651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1037806225 + 524135236 = 32215^2 + 22894^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561941461 - 2² = 1561941457 is a prime.

It is a super-2 number, since 2×1561941461² = 4879322255181629042, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561946461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780970730 + 780970731.

It is an arithmetic number, because the mean of its divisors is an integer number (780970731).

Almost surely, 2^1561941461 is an apocalyptic number.

It is an amenable number.

1561941461 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561941461 is an equidigital number, since it uses as much as digits as its factorization.

1561941461 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25920, while the sum is 38.

The square root of 1561941461 is about 39521.4050990093. The cubic root of 1561941461 is about 1160.2589248108.

The spelling of 1561941461 in words is "one billion, five hundred sixty-one million, nine hundred forty-one thousand, four hundred sixty-one".