21500016 has 40 divisors (see below), whose sum is σ = 55730064. Its totient is φ = 7142400.

The previous prime is 21499981. The next prime is 21500021. The reversal of 21500016 is 61000512.

It is a junction number, because it is equal to n+sod(n) for n = 21499968 and 21500004.

It is a congruent number.

It is an unprimeable number.

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, 18690 + ... + 19806.

Almost surely, 2^21500016 is an apocalyptic number.

It is an amenable number.

21500016 is an abundant number, since it is smaller than the sum of its proper divisors (34230048).

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

21500016 is a wasteful number, since it uses less digits than its factorization.

21500016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1529 (or 1523 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 21500016 is about 4636.8109730719. The cubic root of 21500016 is about 278.0649573034.

Adding to 21500016 its reverse (61000512), we get a palindrome (82500528).

The spelling of 21500016 in words is "twenty-one million, five hundred thousand, sixteen".