21208808841 has 16 divisors (see below), whose sum is σ = 30851850240. Its totient is φ = 12852709520.

The previous prime is 21208808821. The next prime is 21208808893. The reversal of 21208808841 is 14880880212.

It is a cyclic number.

It is not a de Polignac number, because 21208808841 - 2¹⁵ = 21208776073 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21208808793 and 21208808802.

It is not an unprimeable number, because it can be changed into a prime (21208808801) 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, 518836 + ... + 558218.

It is an arithmetic number, because the mean of its divisors is an integer number (1928240640).

Almost surely, 2^21208808841 is an apocalyptic number.

It is an amenable number.

21208808841 is a deficient number, since it is larger than the sum of its proper divisors (9643041399).

21208808841 is a wasteful number, since it uses less digits than its factorization.

21208808841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55716.

The product of its (nonzero) digits is 65536, while the sum is 42.

The spelling of 21208808841 in words is "twenty-one billion, two hundred eight million, eight hundred eight thousand, eight hundred forty-one".