21667824026641 has 27 divisors (see below), whose sum is σ = 23588416831473. Its totient is φ = 19894546264320.

The previous prime is 21667824026621. The next prime is 21667824026647. The reversal of 21667824026641 is 14662042876612.

The square root of 21667824026641 is 4654871.

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

It can be written as a sum of positive squares in 4 ways, for example, as 857622314241 + 20810201712400 = 926079^2 + 4561820^2 .

It is not a de Polignac number, because 21667824026641 - 2¹¹ = 21667824024593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21667824026647) 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, 12768310305 + ... + 12768312001.

Almost surely, 2^{21667824026641} is an apocalyptic number.

21667824026641 is the 4654871-st square number.

21667824026641 is the 2327436-th centered octagonal number.

It is an amenable number.

21667824026641 is a deficient number, since it is larger than the sum of its proper divisors (1920592804832).

21667824026641 is an frugal number, since it uses more digits than its factorization.

21667824026641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3842 (or 1921 counting only the distinct ones).

The product of its (nonzero) digits is 9289728, while the sum is 55.

The spelling of 21667824026641 in words is "twenty-one trillion, six hundred sixty-seven billion, eight hundred twenty-four million, twenty-six thousand, six hundred forty-one".