345123421 has 4 divisors (see below), whose sum is σ = 350781244. Its totient is φ = 339465600.

The previous prime is 345123419. The next prime is 345123431. The reversal of 345123421 is 124321543.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18020025 + 327103396 = 4245^2 + 18086^2 .

It is a cyclic number.

It is not a de Polignac number, because 345123421 - 2¹ = 345123419 is a prime.

It is a super-2 number, since 2×345123421² = 238220351445486482, 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 (345123431) 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 3 ways as a sum of consecutive naturals, for example, 2828820 + ... + 2828941.

It is an arithmetic number, because the mean of its divisors is an integer number (87695311).

Almost surely, 2^345123421 is an apocalyptic number.

It is an amenable number.

345123421 is a deficient number, since it is larger than the sum of its proper divisors (5657823).

345123421 is an equidigital number, since it uses as much as digits as its factorization.

345123421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5657822.

The product of its digits is 2880, while the sum is 25.

The square root of 345123421 is about 18577.4977055577. The cubic root of 345123421 is about 701.4415334457.

Adding to 345123421 its reverse (124321543), we get a palindrome (469444964).

The spelling of 345123421 in words is "three hundred forty-five million, one hundred twenty-three thousand, four hundred twenty-one".