349805821 has 4 divisors (see below), whose sum is σ = 370382652. Its totient is φ = 329228992.

The previous prime is 349805803. The next prime is 349805857. The reversal of 349805821 is 128508943.

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 155900196 + 193905625 = 12486^2 + 13925^2 .

It is a cyclic number.

It is not a de Polignac number, because 349805821 - 2¹³ = 349797629 is a prime.

It is a super-2 number, since 2×349805821² = 244728224810968082, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (349800821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10288390 + ... + 10288423.

It is an arithmetic number, because the mean of its divisors is an integer number (92595663).

Almost surely, 2^349805821 is an apocalyptic number.

It is an amenable number.

349805821 is a deficient number, since it is larger than the sum of its proper divisors (20576831).

349805821 is a wasteful number, since it uses less digits than its factorization.

349805821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20576830.

The product of its (nonzero) digits is 69120, while the sum is 40.

The square root of 349805821 is about 18703.0965617996. The cubic root of 349805821 is about 704.5995217239.

The spelling of 349805821 in words is "three hundred forty-nine million, eight hundred five thousand, eight hundred twenty-one".