345720021 has 8 divisors (see below), whose sum is σ = 461139744. Its totient is φ = 230390160.

The previous prime is 345720019. The next prime is 345720059. The reversal of 345720021 is 120027543.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 345720021 - 2¹ = 345720019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 345719973 and 345720000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (345720821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12906 + ... + 29291.

It is an arithmetic number, because the mean of its divisors is an integer number (57642468).

Almost surely, 2^345720021 is an apocalyptic number.

It is an amenable number.

345720021 is a deficient number, since it is larger than the sum of its proper divisors (115419723).

345720021 is a wasteful number, since it uses less digits than its factorization.

345720021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44931.

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 345720021 is about 18593.5478325144. The cubic root of 345720021 is about 701.8454846978.

Adding to 345720021 its reverse (120027543), we get a palindrome (465747564).

The spelling of 345720021 in words is "three hundred forty-five million, seven hundred twenty thousand, twenty-one".