21015042 has 16 divisors (see below), whose sum is σ = 43055712. Its totient is φ = 6834080.

The previous prime is 21015041. The next prime is 21015047. The reversal of 21015042 is 24051012.

It is not an unprimeable number, because it can be changed into a prime (21015041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42468 + ... + 42959.

It is an arithmetic number, because the mean of its divisors is an integer number (2690982).

Almost surely, 2^21015042 is an apocalyptic number.

21015042 is an abundant number, since it is smaller than the sum of its proper divisors (22040670).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21015042 is a wasteful number, since it uses less digits than its factorization.

21015042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85473.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21015042 is about 4584.2166179185. The cubic root of 21015042 is about 275.9582745156.

Adding to 21015042 its reverse (24051012), we get a palindrome (45066054).

The spelling of 21015042 in words is "twenty-one million, fifteen thousand, forty-two".