661116501 has 12 divisors (see below), whose sum is σ = 963708460. Its totient is φ = 436700160.

The previous prime is 661116493. The next prime is 661116517. The reversal of 661116501 is 105611166.

661116501 is a `hidden beast` number, since 6 + 6 + 1 + 1 + 1 + 650 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 588014001 + 73102500 = 24249^2 + 8550^2 .

It is not a de Polignac number, because 661116501 - 2³ = 661116493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661116551) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 335980 + ... + 337941.

Almost surely, 2^661116501 is an apocalyptic number.

It is an amenable number.

661116501 is a deficient number, since it is larger than the sum of its proper divisors (302591959).

661116501 is a wasteful number, since it uses less digits than its factorization.

661116501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 674036 (or 674033 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The square root of 661116501 is about 25712.1858464036. The cubic root of 661116501 is about 871.1494477784.

Adding to 661116501 its reverse (105611166), we get a palindrome (766727667).

The spelling of 661116501 in words is "six hundred sixty-one million, one hundred sixteen thousand, five hundred one".