345221521 has 2 divisors, whose sum is σ = 345221522. Its totient is φ = 345221520.

The previous prime is 345221519. The next prime is 345221557. The reversal of 345221521 is 125122543.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 289510225 + 55711296 = 17015^2 + 7464^2 .

It is a cyclic number.

It is not a de Polignac number, because 345221521 - 2¹ = 345221519 is a prime.

Together with 345221519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (345224521) 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 as a sum of consecutive naturals, namely, 172610760 + 172610761.

It is an arithmetic number, because the mean of its divisors is an integer number (172610761).

Almost surely, 2^345221521 is an apocalyptic number.

It is an amenable number.

345221521 is a deficient number, since it is larger than the sum of its proper divisors (1).

345221521 is an equidigital number, since it uses as much as digits as its factorization.

345221521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2400, while the sum is 25.

The square root of 345221521 is about 18580.1378089615. The cubic root of 345221521 is about 701.5079878323.

The spelling of 345221521 in words is "three hundred forty-five million, two hundred twenty-one thousand, five hundred twenty-one".