21738848481 has 135 divisors (see below), whose sum is σ = 39584098931. Its totient is φ = 11493320832.

The previous prime is 21738848473. The next prime is 21738848491. The reversal of 21738848481 is 18484883712.

The square root of 21738848481 is 147441.

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

21738848481 is a `hidden beast` number, since 2 + 1 + 7 + 3 + 88 + 484 + 81 = 666.

It can be written as a sum of positive squares in only one way, i.e., 16924709025 + 4814139456 = 130095^2 + 69384^2 .

It is not a de Polignac number, because 21738848481 - 2³ = 21738848473 is a prime.

It is a super-2 number, since 2×21738848481² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21738848441) by changing a digit.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 368455030 + ... + 368455088.

Almost surely, 2^21738848481 is an apocalyptic number.

21738848481 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21738848481 is the 147441-st square number.

21738848481 is the 73721-st centered octagonal number.

It is an amenable number.

21738848481 is a deficient number, since it is larger than the sum of its proper divisors (17845250450).

21738848481 is an frugal number, since it uses more digits than its factorization.

21738848481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186 (or 86 counting only the distinct ones).

The product of its digits is 2752512, while the sum is 54.

The spelling of 21738848481 in words is "twenty-one billion, seven hundred thirty-eight million, eight hundred forty-eight thousand, four hundred eighty-one".