42405309 has 16 divisors (see below), whose sum is σ = 63855040. Its totient is φ = 27805680.

The previous prime is 42405287. The next prime is 42405313. The reversal of 42405309 is 90350424.

It is not a de Polignac number, because 42405309 - 2¹¹ = 42403261 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42405329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11227 + ... + 14520.

It is an arithmetic number, because the mean of its divisors is an integer number (3990940).

Almost surely, 2^42405309 is an apocalyptic number.

It is an amenable number.

42405309 is a deficient number, since it is larger than the sum of its proper divisors (21449731).

42405309 is a wasteful number, since it uses less digits than its factorization.

42405309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25817 (or 25811 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 42405309 is about 6511.9358872765. The cubic root of 42405309 is about 348.7172335963.

The spelling of 42405309 in words is "forty-two million, four hundred five thousand, three hundred nine".