21501516 has 12 divisors (see below), whose sum is σ = 50170232. Its totient is φ = 7167168.

The previous prime is 21501511. The next prime is 21501553. The reversal of 21501516 is 61510512.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 21501492 and 21501501.

It is not an unprimeable number, because it can be changed into a prime (21501511) 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, 895885 + ... + 895908.

Almost surely, 2^21501516 is an apocalyptic number.

It is an amenable number.

21501516 is an abundant number, since it is smaller than the sum of its proper divisors (28668716).

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

21501516 is a wasteful number, since it uses less digits than its factorization.

21501516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1791800 (or 1791798 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 21.

The square root of 21501516 is about 4636.9727193504. The cubic root of 21501516 is about 278.0714237751.

The spelling of 21501516 in words is "twenty-one million, five hundred one thousand, five hundred sixteen".