915880561 has 4 divisors (see below), whose sum is σ = 915950500. Its totient is φ = 915810624.

The previous prime is 915880549. The next prime is 915880583. The reversal of 915880561 is 165088519.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 611028961 + 304851600 = 24719^2 + 17460^2 .

It is a cyclic number.

It is not a de Polignac number, because 915880561 - 2¹³ = 915872369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (915880061) 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, 8796 + ... + 43693.

It is an arithmetic number, because the mean of its divisors is an integer number (228987625).

Almost surely, 2^915880561 is an apocalyptic number.

It is an amenable number.

915880561 is a deficient number, since it is larger than the sum of its proper divisors (69939).

915880561 is a wasteful number, since it uses less digits than its factorization.

915880561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69938.

The product of its (nonzero) digits is 86400, while the sum is 43.

The square root of 915880561 is about 30263.5186486965. The cubic root of 915880561 is about 971.1350163655.

The spelling of 915880561 in words is "nine hundred fifteen million, eight hundred eighty thousand, five hundred sixty-one".