1561661150015 has 16 divisors (see below), whose sum is σ = 1900724507136. Its totient is φ = 1231514407200.

The previous prime is 1561661149967. The next prime is 1561661150017. The reversal of 1561661150015 is 5100511661651.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-1561661150015 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561661150017) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1630430 + ... + 2404500.

It is an arithmetic number, because the mean of its divisors is an integer number (118795281696).

Almost surely, 2^{1561661150015} is an apocalyptic number.

1561661150015 is a deficient number, since it is larger than the sum of its proper divisors (339063357121).

1561661150015 is an equidigital number, since it uses as much as digits as its factorization.

1561661150015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 779830.

The product of its (nonzero) digits is 27000, while the sum is 38.

The spelling of 1561661150015 in words is "one trillion, five hundred sixty-one billion, six hundred sixty-one million, one hundred fifty thousand, fifteen".