21495129328656 has 135 divisors (see below), whose sum is σ = 60586317689079. Its totient is φ = 7114210891776.

The previous prime is 21495129328577. The next prime is 21495129328663. The reversal of 21495129328656 is 65682392159412.

The square root of 21495129328656 is 4636284.

It is a perfect power (a square), and thus also a powerful number.

21495129328656 is a `hidden beast` number, since 2 + 1 + 4 + 9 + 512 + 9 + 32 + 86 + 5 + 6 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2275813616400 + 19219315712256 = 1508580^2 + 4383984^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21495129328593 and 21495129328602.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 8289674496 + ... + 8289677088.

Almost surely, 2^{21495129328656} is an apocalyptic number.

21495129328656 is the 4636284-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21495129328656

21495129328656 is an abundant number, since it is smaller than the sum of its proper divisors (39091188360423).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21495129328656 is an frugal number, since it uses more digits than its factorization.

21495129328656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5498 (or 2747 counting only the distinct ones).

The product of its digits is 55987200, while the sum is 63.

The spelling of 21495129328656 in words is "twenty-one trillion, four hundred ninety-five billion, one hundred twenty-nine million, three hundred twenty-eight thousand, six hundred fifty-six".