42615661565 has 4 divisors (see below), whose sum is σ = 51138793884. Its totient is φ = 34092529248.

The previous prime is 42615661537. The next prime is 42615661589. The reversal of 42615661565 is 56516651624.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15936032644 + 26679628921 = 126238^2 + 163339^2 .

It is a cyclic number.

It is not a de Polignac number, because 42615661565 - 2¹⁶ = 42615596029 is a prime.

It is a super-2 number, since 2×42615661565² (a number of 22 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 3 ways as a sum of consecutive naturals, for example, 4261566152 + ... + 4261566161.

It is an arithmetic number, because the mean of its divisors is an integer number (12784698471).

Almost surely, 2^42615661565 is an apocalyptic number.

It is an amenable number.

42615661565 is a deficient number, since it is larger than the sum of its proper divisors (8523132319).

42615661565 is an equidigital number, since it uses as much as digits as its factorization.

42615661565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8523132318.

The product of its digits is 1296000, while the sum is 47.

The spelling of 42615661565 in words is "forty-two billion, six hundred fifteen million, six hundred sixty-one thousand, five hundred sixty-five".