345490781 has 2 divisors, whose sum is σ = 345490782. Its totient is φ = 345490780.

The previous prime is 345490777. The next prime is 345490807. The reversal of 345490781 is 187094543.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 248566756 + 96924025 = 15766^2 + 9845^2 .

It is an emirp because it is prime and its reverse (187094543) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 345490781 - 2² = 345490777 is a prime.

It is a super-2 number, since 2×345490781² = 238727759511979922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (345490721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 172745390 + 172745391.

It is an arithmetic number, because the mean of its divisors is an integer number (172745391).

Almost surely, 2^345490781 is an apocalyptic number.

It is an amenable number.

345490781 is a deficient number, since it is larger than the sum of its proper divisors (1).

345490781 is an equidigital number, since it uses as much as digits as its factorization.

345490781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120960, while the sum is 41.

The square root of 345490781 is about 18587.3823062851. The cubic root of 345490781 is about 701.6903238514.

The spelling of 345490781 in words is "three hundred forty-five million, four hundred ninety thousand, seven hundred eighty-one".