21530355415 has 16 divisors (see below), whose sum is σ = 27437428512. Its totient is φ = 16162965504.

The previous prime is 21530355409. The next prime is 21530355433. The reversal of 21530355415 is 51455303512.

It is a cyclic number.

It is not a de Polignac number, because 21530355415 - 2²¹ = 21528258263 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 347169 + ... + 404458.

It is an arithmetic number, because the mean of its divisors is an integer number (1714839282).

Almost surely, 2^21530355415 is an apocalyptic number.

21530355415 is a deficient number, since it is larger than the sum of its proper divisors (5907073097).

21530355415 is a wasteful number, since it uses less digits than its factorization.

21530355415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 751986.

The product of its (nonzero) digits is 45000, while the sum is 34.

Adding to 21530355415 its reverse (51455303512), we get a palindrome (72985658927).

The spelling of 21530355415 in words is "twenty-one billion, five hundred thirty million, three hundred fifty-five thousand, four hundred fifteen".