21516042 has 16 divisors (see below), whose sum is σ = 43738272. Its totient is φ = 7054320.

The previous prime is 21516041. The next prime is 21516071. The reversal of 21516042 is 24061512.

It is not an unprimeable number, because it can be changed into a prime (21516041) 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, 29028 + ... + 29759.

It is an arithmetic number, because the mean of its divisors is an integer number (2733642).

Almost surely, 2^21516042 is an apocalyptic number.

21516042 is an abundant number, since it is smaller than the sum of its proper divisors (22222230).

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

21516042 is a wasteful number, since it uses less digits than its factorization.

21516042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58853.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 21516042 is about 4638.5387785379. The cubic root of 21516042 is about 278.1340295347.

Adding to 21516042 its reverse (24061512), we get a palindrome (45577554).

The spelling of 21516042 in words is "twenty-one million, five hundred sixteen thousand, forty-two".