21038447738881 has 4 divisors (see below), whose sum is σ = 22145734462000. Its totient is φ = 19931161015764.

The previous prime is 21038447738813. The next prime is 21038447738887. The reversal of 21038447738881 is 18883774483012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21038447738881 - 2¹⁹ = 21038447214593 is a prime.

It is a super-2 number, since 2×21038447738881² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21038447738887) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 553643361531 + ... + 553643361568.

It is an arithmetic number, because the mean of its divisors is an integer number (5536433615500).

Almost surely, 2^{21038447738881} is an apocalyptic number.

It is an amenable number.

21038447738881 is a deficient number, since it is larger than the sum of its proper divisors (1107286723119).

21038447738881 is a wasteful number, since it uses less digits than its factorization.

21038447738881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1107286723118.

The product of its (nonzero) digits is 57802752, while the sum is 64.

The spelling of 21038447738881 in words is "twenty-one trillion, thirty-eight billion, four hundred forty-seven million, seven hundred thirty-eight thousand, eight hundred eighty-one".