1561737356761 has 4 divisors (see below), whose sum is σ = 1629638980992. Its totient is φ = 1493835732532.

The previous prime is 1561737356731. The next prime is 1561737356783. The reversal of 1561737356761 is 1676537371651.

It is a happy number.

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 1561737356761 - 2¹⁷ = 1561737225689 is a prime.

It is a super-2 number, since 2×1561737356761² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1561737356696 and 1561737356705.

It is not an unprimeable number, because it can be changed into a prime (1561737356731) 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, 33950812081 + ... + 33950812126.

It is an arithmetic number, because the mean of its divisors is an integer number (407409745248).

Almost surely, 2^{1561737356761} is an apocalyptic number.

It is an amenable number.

1561737356761 is a deficient number, since it is larger than the sum of its proper divisors (67901624231).

1561737356761 is an equidigital number, since it uses as much as digits as its factorization.

1561737356761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67901624230.

The product of its digits is 16669800, while the sum is 58.

The spelling of 1561737356761 in words is "one trillion, five hundred sixty-one billion, seven hundred thirty-seven million, three hundred fifty-six thousand, seven hundred sixty-one".