42021005 has 18 divisors (see below), whose sum is σ = 54848394. Its totient is φ = 30891744.

The previous prime is 42020983. The next prime is 42021017. The reversal of 42021005 is 50012024.

It can be written as a sum of positive squares in 3 ways, for example, as 198916 + 41822089 = 446^2 + 6467^2 .

It is not a de Polignac number, because 42021005 - 2¹⁰ = 42019981 is a prime.

It is a super-2 number, since 2×42021005² = 3531529722420050, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 188324 + ... + 188546.

It is an arithmetic number, because the mean of its divisors is an integer number (3047133).

Almost surely, 2^42021005 is an apocalyptic number.

It is an amenable number.

42021005 is a deficient number, since it is larger than the sum of its proper divisors (12827389).

42021005 is an equidigital number, since it uses as much as digits as its factorization.

42021005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 477 (or 241 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 14.

The square root of 42021005 is about 6482.3610667719. The cubic root of 42021005 is about 347.6606024023.

Multiplying 42021005 by its product of nonzero digits (80), we get a square (3361680400 = 57980²).

Adding to 42021005 its reverse (50012024), we get a palindrome (92033029).

It can be divided in two parts, 420 and 21005, that multiplied together give a triangular number (8822100 = T₄₂₀₀).

The spelling of 42021005 in words is "forty-two million, twenty-one thousand, five".