661500115 has 4 divisors (see below), whose sum is σ = 793800144. Its totient is φ = 529200088.

The previous prime is 661500061. The next prime is 661500131. The reversal of 661500115 is 511005166.

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

It is a cyclic number.

It is not a de Polignac number, because 661500115 - 2¹³ = 661491923 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 661500115.

It is an unprimeable number.

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, 66150007 + ... + 66150016.

It is an arithmetic number, because the mean of its divisors is an integer number (198450036).

Almost surely, 2^661500115 is an apocalyptic number.

661500115 is a deficient number, since it is larger than the sum of its proper divisors (132300029).

661500115 is a wasteful number, since it uses less digits than its factorization.

661500115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132300028.

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 661500115 is about 25719.6445348687. The cubic root of 661500115 is about 871.3179105266.

The spelling of 661500115 in words is "six hundred sixty-one million, five hundred thousand, one hundred fifteen".