42817021 has 16 divisors (see below), whose sum is σ = 48106800. Its totient is φ = 37836288.

The previous prime is 42817009. The next prime is 42817063. The reversal of 42817021 is 12071824.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 436921 + 42380100 = 661^2 + 6510^2 .

It is a cyclic number.

It is not a de Polignac number, because 42817021 - 2⁵ = 42816989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42817001) 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, 51235 + ... + 52063.

It is an arithmetic number, because the mean of its divisors is an integer number (3006675).

Almost surely, 2^42817021 is an apocalyptic number.

It is an amenable number.

42817021 is a deficient number, since it is larger than the sum of its proper divisors (5289779).

42817021 is a wasteful number, since it uses less digits than its factorization.

42817021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1008.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 42817021 is about 6543.4716320926. The cubic root of 42817021 is about 349.8421628455.

Adding to 42817021 its reverse (12071824), we get a palindrome (54888845).

The spelling of 42817021 in words is "forty-two million, eight hundred seventeen thousand, twenty-one".