21621171263563 has 16 divisors (see below), whose sum is σ = 23261912311680. Its totient is φ = 20023178213376.

The previous prime is 21621171263551. The next prime is 21621171263581. The reversal of 21621171263563 is 36536217112612.

It is a cyclic number.

It is not a de Polignac number, because 21621171263563 - 2²¹ = 21621169166411 is a prime.

It is a super-2 number, since 2×21621171263563² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21621171263543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27079470 + ... + 27866467.

It is an arithmetic number, because the mean of its divisors is an integer number (1453869519480).

Almost surely, 2^{21621171263563} is an apocalyptic number.

21621171263563 is a deficient number, since it is larger than the sum of its proper divisors (1640741048117).

21621171263563 is a wasteful number, since it uses less digits than its factorization.

21621171263563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54946326.

The product of its digits is 544320, while the sum is 46.

The spelling of 21621171263563 in words is "twenty-one trillion, six hundred twenty-one billion, one hundred seventy-one million, two hundred sixty-three thousand, five hundred sixty-three".