1617157561 has 4 divisors (see below), whose sum is σ = 1633169124. Its totient is φ = 1601146000.

The previous prime is 1617157559. The next prime is 1617157567. The reversal of 1617157561 is 1657517161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1657517161 = 101 ⋅16411061.

It can be written as a sum of positive squares in 2 ways, for example, as 1228081936 + 389075625 = 35044^2 + 19725^2 .

It is a cyclic number.

It is not a de Polignac number, because 1617157561 - 2¹ = 1617157559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1617157567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8005630 + ... + 8005831.

It is an arithmetic number, because the mean of its divisors is an integer number (408292281).

Almost surely, 2^1617157561 is an apocalyptic number.

It is an amenable number.

1617157561 is a deficient number, since it is larger than the sum of its proper divisors (16011563).

1617157561 is a wasteful number, since it uses less digits than its factorization.

1617157561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16011562.

The product of its digits is 44100, while the sum is 40.

The square root of 1617157561 is about 40213.8976101546. The cubic root of 1617157561 is about 1173.7729906810.

The spelling of 1617157561 in words is "one billion, six hundred seventeen million, one hundred fifty-seven thousand, five hundred sixty-one".