1561701561 has 32 divisors (see below), whose sum is σ = 2509839360. Its totient is φ = 843794496.

The previous prime is 1561701461. The next prime is 1561701611. The reversal of 1561701561 is 1651071651.

It is not a de Polignac number, because 1561701561 - 2¹⁵ = 1561668793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1561701061) 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 in 31 ways as a sum of consecutive naturals, for example, 218730 + ... + 225756.

It is an arithmetic number, because the mean of its divisors is an integer number (78432480).

Almost surely, 2^1561701561 is an apocalyptic number.

It is an amenable number.

1561701561 is a deficient number, since it is larger than the sum of its proper divisors (948137799).

1561701561 is a wasteful number, since it uses less digits than its factorization.

1561701561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7613.

The product of its (nonzero) digits is 6300, while the sum is 33.

The square root of 1561701561 is about 39518.3699183051. The cubic root of 1561701561 is about 1160.1995200306.

The spelling of 1561701561 in words is "one billion, five hundred sixty-one million, seven hundred one thousand, five hundred sixty-one".