21150353521 has 8 divisors (see below), whose sum is σ = 23635872288. Its totient is φ = 18758628000.

The previous prime is 21150353503. The next prime is 21150353537. The reversal of 21150353521 is 12535305112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21150353521 - 2¹⁵ = 21150320753 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21150353521.

It is not an unprimeable number, because it can be changed into a prime (21150323521) 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, 23447835 + ... + 23448736.

It is an arithmetic number, because the mean of its divisors is an integer number (2954484036).

Almost surely, 2^21150353521 is an apocalyptic number.

It is an amenable number.

21150353521 is a deficient number, since it is larger than the sum of its proper divisors (2485518767).

21150353521 is a wasteful number, since it uses less digits than its factorization.

21150353521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46896623.

The product of its (nonzero) digits is 4500, while the sum is 28.

Adding to 21150353521 its reverse (12535305112), we get a palindrome (33685658633).

The spelling of 21150353521 in words is "twenty-one billion, one hundred fifty million, three hundred fifty-three thousand, five hundred twenty-one".