290531981 has 2 divisors, whose sum is σ = 290531982. Its totient is φ = 290531980.

The previous prime is 290531977. The next prime is 290532013. The reversal of 290531981 is 189135092.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 285948100 + 4583881 = 16910^2 + 2141^2 .

It is a cyclic number.

It is not a de Polignac number, because 290531981 - 2² = 290531977 is a prime.

It is a super-2 number, since 2×290531981² = 168817663967568722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (290531911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 145265990 + 145265991.

It is an arithmetic number, because the mean of its divisors is an integer number (145265991).

Almost surely, 2^290531981 is an apocalyptic number.

It is an amenable number.

290531981 is a deficient number, since it is larger than the sum of its proper divisors (1).

290531981 is an equidigital number, since it uses as much as digits as its factorization.

290531981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 38.

The square root of 290531981 is about 17044.9987092989. The cubic root of 290531981 is about 662.3150876363.

The spelling of 290531981 in words is "two hundred ninety million, five hundred thirty-one thousand, nine hundred eighty-one".