501655661 has 8 divisors (see below), whose sum is σ = 540512280. Its totient is φ = 462837312.

The previous prime is 501655633. The next prime is 501655729. The reversal of 501655661 is 166556105.

It can be written as a sum of positive squares in 4 ways, for example, as 26677225 + 474978436 = 5165^2 + 21794^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 501655661 - 2¹⁸ = 501393517 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 (501655621) 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 7 ways as a sum of consecutive naturals, for example, 21395 + ... + 38223.

It is an arithmetic number, because the mean of its divisors is an integer number (67564035).

Almost surely, 2^501655661 is an apocalyptic number.

It is an amenable number.

501655661 is a deficient number, since it is larger than the sum of its proper divisors (38856619).

501655661 is a wasteful number, since it uses less digits than its factorization.

501655661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19135.

The product of its (nonzero) digits is 27000, while the sum is 35.

The square root of 501655661 is about 22397.6708833754. The cubic root of 501655661 is about 794.5756267845.

The spelling of 501655661 in words is "five hundred one million, six hundred fifty-five thousand, six hundred sixty-one".