349405840 has 80 divisors (see below), whose sum is σ = 930976128. Its totient is φ = 119467008.

The previous prime is 349405799. The next prime is 349405843. The reversal of 349405840 is 48504943.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×349405840² = 244168882052211200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 349405840.

It is not an unprimeable number, because it can be changed into a prime (349405843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 292284 + ... + 293476.

Almost surely, 2^349405840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 349405840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (465488064).

349405840 is an abundant number, since it is smaller than the sum of its proper divisors (581570288).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

349405840 is a wasteful number, since it uses less digits than its factorization.

349405840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1736 (or 1730 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 37.

The square root of 349405840 is about 18692.4005948942. The cubic root of 349405840 is about 704.3308641911.

The spelling of 349405840 in words is "three hundred forty-nine million, four hundred five thousand, eight hundred forty".