42115021 has 4 divisors (see below), whose sum is σ = 45354652. Its totient is φ = 38875392.

The previous prime is 42115009. The next prime is 42115027. The reversal of 42115021 is 12051124.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1932100 + 40182921 = 1390^2 + 6339^2 .

It is a cyclic number.

It is not a de Polignac number, because 42115021 - 2⁷ = 42114893 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 42114986 and 42115004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42115027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1619796 + ... + 1619821.

It is an arithmetic number, because the mean of its divisors is an integer number (11338663).

Almost surely, 2^42115021 is an apocalyptic number.

It is an amenable number.

42115021 is a deficient number, since it is larger than the sum of its proper divisors (3239631).

42115021 is a wasteful number, since it uses less digits than its factorization.

42115021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3239630.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 42115021 is about 6489.6086939044. The cubic root of 42115021 is about 347.9196895973.

Adding to 42115021 its reverse (12051124), we get a palindrome (54166145).

The spelling of 42115021 in words is "forty-two million, one hundred fifteen thousand, twenty-one".