21512454452 has 12 divisors (see below), whose sum is σ = 37648150596. Its totient is φ = 10755840000.

The previous prime is 21512454377. The next prime is 21512454487. The reversal of 21512454452 is 25445421512.

It can be written as a sum of positive squares in 2 ways, for example, as 15929973796 + 5582480656 = 126214^2 + 74716^2 .

It is a congruent number.

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, 54452 + ... + 214452.

It is an arithmetic number, because the mean of its divisors is an integer number (3137345883).

Almost surely, 2^21512454452 is an apocalyptic number.

It is an amenable number.

21512454452 is a deficient number, since it is larger than the sum of its proper divisors (16135696144).

21512454452 is a wasteful number, since it uses less digits than its factorization.

21512454452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193618 (or 193616 counting only the distinct ones).

The product of its digits is 64000, while the sum is 35.

Adding to 21512454452 its reverse (25445421512), we get a palindrome (46957875964).

The spelling of 21512454452 in words is "twenty-one billion, five hundred twelve million, four hundred fifty-four thousand, four hundred fifty-two".