1561215515965 has 16 divisors (see below), whose sum is σ = 2198963014272. Its totient is φ = 1041614057664.

The previous prime is 1561215515953. The next prime is 1561215516023. The reversal of 1561215515965 is 5695155121651.

It is a cyclic number.

It is not a de Polignac number, because 1561215515965 - 2⁵ = 1561215515933 is a prime.

It is a super-2 number, since 2×1561215515965² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 602784619 + ... + 602787208.

It is an arithmetic number, because the mean of its divisors is an integer number (137435188392).

Almost surely, 2^{1561215515965} is an apocalyptic number.

It is an amenable number.

1561215515965 is a deficient number, since it is larger than the sum of its proper divisors (637747498307).

1561215515965 is a wasteful number, since it uses less digits than its factorization.

1561215515965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1205571876.

The product of its digits is 2025000, while the sum is 52.

The spelling of 1561215515965 in words is "one trillion, five hundred sixty-one billion, two hundred fifteen million, five hundred fifteen thousand, nine hundred sixty-five".