510649981 has 2 divisors, whose sum is σ = 510649982. Its totient is φ = 510649980.

The previous prime is 510649973. The next prime is 510649991. The reversal of 510649981 is 189946015.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 430189081 + 80460900 = 20741^2 + 8970^2 .

It is a cyclic number.

It is not a de Polignac number, because 510649981 - 2³ = 510649973 is a prime.

It is a super-2 number, since 2×510649981² = 521526806190600722, which contains 22 as substring.

It is equal to p_26886634 and since 510649981 and 26886634 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (510649991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 255324990 + 255324991.

It is an arithmetic number, because the mean of its divisors is an integer number (255324991).

Almost surely, 2^510649981 is an apocalyptic number.

It is an amenable number.

510649981 is a deficient number, since it is larger than the sum of its proper divisors (1).

510649981 is an equidigital number, since it uses as much as digits as its factorization.

510649981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 77760, while the sum is 43.

The square root of 510649981 is about 22597.5658202382. The cubic root of 510649981 is about 799.2962461989.

The spelling of 510649981 in words is "five hundred ten million, six hundred forty-nine thousand, nine hundred eighty-one".