21531155234 has 8 divisors (see below), whose sum is σ = 32297709468. Its totient is φ = 10765252080.

The previous prime is 21531155227. The next prime is 21531155249. The reversal of 21531155234 is 43255113512.

It can be written as a sum of positive squares in 2 ways, for example, as 21081588025 + 449567209 = 145195^2 + 21203^2 .

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

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21531155234.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69377 + ... + 218804.

Almost surely, 2^21531155234 is an apocalyptic number.

21531155234 is a deficient number, since it is larger than the sum of its proper divisors (10766554234).

21531155234 is a wasteful number, since it uses less digits than its factorization.

21531155234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325540.

The product of its digits is 18000, while the sum is 32.

Adding to 21531155234 its reverse (43255113512), we get a palindrome (64786268746).

The spelling of 21531155234 in words is "twenty-one billion, five hundred thirty-one million, one hundred fifty-five thousand, two hundred thirty-four".