21523516 has 24 divisors (see below), whose sum is σ = 43193696. Its totient is φ = 9192960.

The previous prime is 21523511. The next prime is 21523519. The reversal of 21523516 is 61532512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21523511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8296 + ... + 10576.

Almost surely, 2^21523516 is an apocalyptic number.

It is an amenable number.

21523516 is an abundant number, since it is smaller than the sum of its proper divisors (21670180).

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

21523516 is a wasteful number, since it uses less digits than its factorization.

21523516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2629 (or 2627 counting only the distinct ones).

The product of its digits is 1800, while the sum is 25.

The square root of 21523516 is about 4639.3443502288. The cubic root of 21523516 is about 278.1662308272.

The spelling of 21523516 in words is "twenty-one million, five hundred twenty-three thousand, five hundred sixteen".