21621271263563 has 8 divisors (see below), whose sum is σ = 22509816660768. Its totient is φ = 20748735693504.

The previous prime is 21621271263541. The next prime is 21621271263587. The reversal of 21621271263563 is 36536217212612.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21621271263563 - 2²⁶ = 21621204154699 is a prime.

It is a super-2 number, since 2×21621271263563² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21621271263763) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4002454031 + ... + 4002459432.

It is an arithmetic number, because the mean of its divisors is an integer number (2813727082596).

Almost surely, 2^{21621271263563} is an apocalyptic number.

21621271263563 is a deficient number, since it is larger than the sum of its proper divisors (888545397205).

21621271263563 is an equidigital number, since it uses as much as digits as its factorization.

21621271263563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8004913573.

The product of its digits is 1088640, while the sum is 47.

The spelling of 21621271263563 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred seventy-one million, two hundred sixty-three thousand, five hundred sixty-three".