21530354471 has 4 divisors (see below), whose sum is σ = 21546175344. Its totient is φ = 21514533600.

The previous prime is 21530354467. The next prime is 21530354509. The reversal of 21530354471 is 17445303512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21530354471 - 2² = 21530354467 is a prime.

It is a super-3 number, since 3×21530354471³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530359471) 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, 7908395 + ... + 7911116.

It is an arithmetic number, because the mean of its divisors is an integer number (5386543836).

Almost surely, 2^21530354471 is an apocalyptic number.

21530354471 is a deficient number, since it is larger than the sum of its proper divisors (15820873).

21530354471 is a wasteful number, since it uses less digits than its factorization.

21530354471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15820872.

The product of its (nonzero) digits is 50400, while the sum is 35.

Adding to 21530354471 its reverse (17445303512), we get a palindrome (38975657983).

The spelling of 21530354471 in words is "twenty-one billion, five hundred thirty million, three hundred fifty-four thousand, four hundred seventy-one".