42821581 has 8 divisors (see below), whose sum is σ = 47355264. Its totient is φ = 38394720.

The previous prime is 42821503. The next prime is 42821599. The reversal of 42821581 is 18512824.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 42821581 - 2⁹ = 42821069 is a prime.

It is a super-2 number, since 2×42821581² = 3667375598679122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42821501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25861 + ... + 27466.

It is an arithmetic number, because the mean of its divisors is an integer number (5919408).

Almost surely, 2^42821581 is an apocalyptic number.

It is an amenable number.

42821581 is a deficient number, since it is larger than the sum of its proper divisors (4533683).

42821581 is a wasteful number, since it uses less digits than its factorization.

42821581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53411.

The product of its digits is 5120, while the sum is 31.

The square root of 42821581 is about 6543.8200617071. The cubic root of 42821581 is about 349.8545817668.

The spelling of 42821581 in words is "forty-two million, eight hundred twenty-one thousand, five hundred eighty-one".