21016842 has 32 divisors (see below), whose sum is σ = 52406784. Its totient is φ = 5458800.

The previous prime is 21016837. The next prime is 21016859. The reversal of 21016842 is 24861012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22284 + ... + 23207.

It is an arithmetic number, because the mean of its divisors is an integer number (1637712).

Almost surely, 2^21016842 is an apocalyptic number.

21016842 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21016842 is an abundant number, since it is smaller than the sum of its proper divisors (31389942).

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

21016842 is a wasteful number, since it uses less digits than its factorization.

21016842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45514.

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21016842 is about 4584.4129395158. The cubic root of 21016842 is about 275.9661531693.

Adding to 21016842 its reverse (24861012), we get a palindrome (45877854).

The spelling of 21016842 in words is "twenty-one million, sixteen thousand, eight hundred forty-two".