21111201021 has 8 divisors (see below), whose sum is σ = 29118898080. Its totient is φ = 13588818992.

The previous prime is 21111201011. The next prime is 21111201071. The reversal of 21111201021 is 12010211112.

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 21111201021 - 2²³ = 21102812413 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21111200988 and 21111201006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111201011) 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, 121328655 + ... + 121328828.

It is an arithmetic number, because the mean of its divisors is an integer number (3639862260).

Almost surely, 2^21111201021 is an apocalyptic number.

It is an amenable number.

21111201021 is a deficient number, since it is larger than the sum of its proper divisors (8007697059).

21111201021 is a wasteful number, since it uses less digits than its factorization.

21111201021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242657515.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21111201021 its reverse (12010211112), we get a palindrome (33121412133).

The spelling of 21111201021 in words is "twenty-one billion, one hundred eleven million, two hundred one thousand, twenty-one".