21531450415 has 32 divisors (see below), whose sum is σ = 26892518400. Its totient is φ = 16537194240.

The previous prime is 21531450379. The next prime is 21531450433. The reversal of 21531450415 is 51405413512.

It is not a de Polignac number, because 21531450415 - 2¹⁹ = 21530926127 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5478171 + ... + 5482099.

It is an arithmetic number, because the mean of its divisors is an integer number (840391200).

Almost surely, 2^21531450415 is an apocalyptic number.

21531450415 is a deficient number, since it is larger than the sum of its proper divisors (5361067985).

21531450415 is a wasteful number, since it uses less digits than its factorization.

21531450415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4407.

The product of its (nonzero) digits is 12000, while the sum is 31.

Adding to 21531450415 its reverse (51405413512), we get a palindrome (72936863927).

The spelling of 21531450415 in words is "twenty-one billion, five hundred thirty-one million, four hundred fifty thousand, four hundred fifteen".