506661989 has 2 divisors, whose sum is σ = 506661990. Its totient is φ = 506661988.

The previous prime is 506661983. The next prime is 506662001. The reversal of 506661989 is 989166605.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 503239489 + 3422500 = 22433^2 + 1850^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-506661989 is a prime.

It is a super-2 number, since 2×506661989² = 513412742194872242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (506661983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 253330994 + 253330995.

It is an arithmetic number, because the mean of its divisors is an integer number (253330995).

Almost surely, 2^506661989 is an apocalyptic number.

It is an amenable number.

506661989 is a deficient number, since it is larger than the sum of its proper divisors (1).

506661989 is an equidigital number, since it uses as much as digits as its factorization.

506661989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 699840, while the sum is 50.

The square root of 506661989 is about 22509.1534492082. The cubic root of 506661989 is about 797.2100675944.

The spelling of 506661989 in words is "five hundred six million, six hundred sixty-one thousand, nine hundred eighty-nine".