21125554211 has 4 divisors (see below), whose sum is σ = 22044056592. Its totient is φ = 20207051832.

The previous prime is 21125554183. The next prime is 21125554267. The reversal of 21125554211 is 11245552112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21125554211 - 2⁶ = 21125554147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21125554291) 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, 459251156 + ... + 459251201.

It is an arithmetic number, because the mean of its divisors is an integer number (5511014148).

Almost surely, 2^21125554211 is an apocalyptic number.

21125554211 is a deficient number, since it is larger than the sum of its proper divisors (918502381).

21125554211 is an equidigital number, since it uses as much as digits as its factorization.

21125554211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 918502380.

The product of its digits is 4000, while the sum is 29.

The spelling of 21125554211 in words is "twenty-one billion, one hundred twenty-five million, five hundred fifty-four thousand, two hundred eleven".