506995981 has 12 divisors (see below), whose sum is σ = 566566812. Its totient is φ = 452052864.

The previous prime is 506995963. The next prime is 506995999. The reversal of 506995981 is 189599605.

It is an interprime number because it is at equal distance from previous prime (506995963) and next prime (506995999).

It can be written as a sum of positive squares in 2 ways, for example, as 389707081 + 117288900 = 19741^2 + 10830^2 .

It is a de Polignac number, because none of the positive numbers 2^k-506995981 is a prime.

It is a super-2 number, since 2×506995981² = 514089849500304722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (506995481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35170 + ... + 47443.

It is an arithmetic number, because the mean of its divisors is an integer number (47213901).

Almost surely, 2^506995981 is an apocalyptic number.

It is an amenable number.

506995981 is a deficient number, since it is larger than the sum of its proper divisors (59570831).

506995981 is a wasteful number, since it uses less digits than its factorization.

506995981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82668 (or 82649 counting only the distinct ones).

The product of its (nonzero) digits is 874800, while the sum is 52.

The square root of 506995981 is about 22516.5712531904. The cubic root of 506995981 is about 797.3852029611.

The spelling of 506995981 in words is "five hundred six million, nine hundred ninety-five thousand, nine hundred eighty-one".