21845135601 has 27 divisors (see below), whose sum is σ = 33315081579. Its totient is φ = 13791606912.

The previous prime is 21845135591. The next prime is 21845135633. The reversal of 21845135601 is 10653154812.

The square root of 21845135601 is 147801.

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

21845135601 is a `hidden beast` number, since 2 + 1 + 8 + 45 + 1 + 3 + 5 + 601 = 666.

It can be written as a sum of positive squares in only one way, i.e., 13191671025 + 8653464576 = 114855^2 + 93024^2 .

It is not a de Polignac number, because 21845135601 - 2¹⁷ = 21845004529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21845135101) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 8423361 + ... + 8425953.

Almost surely, 2^21845135601 is an apocalyptic number.

21845135601 is the 147801-st square number.

21845135601 is the 73901-st centered octagonal number.

It is an amenable number.

21845135601 is a deficient number, since it is larger than the sum of its proper divisors (11469945978).

21845135601 is an frugal number, since it uses more digits than its factorization.

21845135601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5230 (or 2615 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

Multiplying 21845135601 by its sum of digits (36), we get a square (786424881636 = 886806²).

The spelling of 21845135601 in words is "twenty-one billion, eight hundred forty-five million, one hundred thirty-five thousand, six hundred one".