21530205151 has 16 divisors (see below), whose sum is σ = 26533620288. Its totient is φ = 17012448000.

The previous prime is 21530205133. The next prime is 21530205161. The reversal of 21530205151 is 15150203512.

It is a cyclic number.

It is not a de Polignac number, because 21530205151 - 2¹¹ = 21530203103 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530205161) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 86200 + ... + 224701.

It is an arithmetic number, because the mean of its divisors is an integer number (1658351268).

Almost surely, 2^21530205151 is an apocalyptic number.

21530205151 is a deficient number, since it is larger than the sum of its proper divisors (5003415137).

21530205151 is a wasteful number, since it uses less digits than its factorization.

21530205151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311682.

The product of its (nonzero) digits is 1500, while the sum is 25.

Adding to 21530205151 its reverse (15150203512), we get a palindrome (36680408663).

The spelling of 21530205151 in words is "twenty-one billion, five hundred thirty million, two hundred five thousand, one hundred fifty-one".