42821405 has 16 divisors (see below), whose sum is σ = 56476224. Its totient is φ = 30910080.

The previous prime is 42821399. The next prime is 42821407. The reversal of 42821405 is 50412824.

It is a happy number.

It is not a de Polignac number, because 42821405 - 2⁶ = 42821341 is a prime.

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 (42821407) 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, 4694 + ... + 10376.

It is an arithmetic number, because the mean of its divisors is an integer number (3529764).

Almost surely, 2^42821405 is an apocalyptic number.

It is an amenable number.

42821405 is a deficient number, since it is larger than the sum of its proper divisors (13654819).

42821405 is a wasteful number, since it uses less digits than its factorization.

42821405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5836.

The product of its (nonzero) digits is 2560, while the sum is 26.

The square root of 42821405 is about 6543.8066138907. The cubic root of 42821405 is about 349.8541024563.

It can be divided in two parts, 428 and 21405, that multiplied together give a triangular number (9161340 = T₄₂₈₀).

The spelling of 42821405 in words is "forty-two million, eight hundred twenty-one thousand, four hundred five".