1561064166461 has 4 divisors (see below), whose sum is σ = 1643225438400. Its totient is φ = 1478902894524.

The previous prime is 1561064166437. The next prime is 1561064166559. The reversal of 1561064166461 is 1646614601651.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1561064166461 - 2¹⁸ = 1561063904317 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 (1561064166421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41080635941 + ... + 41080635978.

It is an arithmetic number, because the mean of its divisors is an integer number (410806359600).

Almost surely, 2^{1561064166461} is an apocalyptic number.

It is an amenable number.

1561064166461 is a deficient number, since it is larger than the sum of its proper divisors (82161271939).

1561064166461 is an equidigital number, since it uses as much as digits as its factorization.

1561064166461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82161271938.

The product of its (nonzero) digits is 622080, while the sum is 47.

The spelling of 1561064166461 in words is "one trillion, five hundred sixty-one billion, sixty-four million, one hundred sixty-six thousand, four hundred sixty-one".