506651661 has 12 divisors (see below), whose sum is σ = 739376092. Its totient is φ = 334285056.

The previous prime is 506651611. The next prime is 506651687. The reversal of 506651661 is 166156605.

It can be written as a sum of positive squares in 2 ways, for example, as 272745225 + 233906436 = 16515^2 + 15294^2 .

It is not a de Polignac number, because 506651661 - 2⁷ = 506651533 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 (506651611) 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, 289306 + ... + 291051.

Almost surely, 2^506651661 is an apocalyptic number.

It is an amenable number.

506651661 is a deficient number, since it is larger than the sum of its proper divisors (232724431).

506651661 is a wasteful number, since it uses less digits than its factorization.

506651661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 580460 (or 580457 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 506651661 is about 22508.9240302596. The cubic root of 506651661 is about 797.2046506750.

It can be divided in two parts, 50665 and 1661, that added together give a triangular number (52326 = T₃₂₃).

The spelling of 506651661 in words is "five hundred six million, six hundred fifty-one thousand, six hundred sixty-one".