345945721 has 4 divisors (see below), whose sum is σ = 377395344. Its totient is φ = 314496100.

The previous prime is 345945703. The next prime is 345945739. The reversal of 345945721 is 127549543.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 127549543 = 11 ⋅11595413.

It is an interprime number because it is at equal distance from previous prime (345945703) and next prime (345945739).

It is a cyclic number.

It is not a de Polignac number, because 345945721 - 2⁹ = 345945209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (345945751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15724795 + ... + 15724816.

It is an arithmetic number, because the mean of its divisors is an integer number (94348836).

Almost surely, 2^345945721 is an apocalyptic number.

It is an amenable number.

345945721 is a deficient number, since it is larger than the sum of its proper divisors (31449623).

345945721 is a wasteful number, since it uses less digits than its factorization.

345945721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31449622.

The product of its digits is 151200, while the sum is 40.

The square root of 345945721 is about 18599.6161519532. The cubic root of 345945721 is about 701.9981825046.

The spelling of 345945721 in words is "three hundred forty-five million, nine hundred forty-five thousand, seven hundred twenty-one".