42055821 has 8 divisors (see below), whose sum is σ = 62304960. Its totient is φ = 28037196.

The previous prime is 42055817. The next prime is 42055831. The reversal of 42055821 is 12855024.

It is a happy number.

It is not a de Polignac number, because 42055821 - 2² = 42055817 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 1557623 = 42055821 / (4 + 2 + 0 + 5 + 5 + 8 + 2 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42055831) 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 7 ways as a sum of consecutive naturals, for example, 778785 + ... + 778838.

It is an arithmetic number, because the mean of its divisors is an integer number (7788120).

Almost surely, 2^42055821 is an apocalyptic number.

It is an amenable number.

42055821 is a deficient number, since it is larger than the sum of its proper divisors (20249139).

42055821 is a wasteful number, since it uses less digits than its factorization.

42055821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1557632 (or 1557626 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 42055821 is about 6485.0459520346. The cubic root of 42055821 is about 347.7565925716.

The spelling of 42055821 in words is "forty-two million, fifty-five thousand, eight hundred twenty-one".