21111222021 has 8 divisors (see below), whose sum is σ = 28151055264. Its totient is φ = 14072768400.

The previous prime is 21111222019. The next prime is 21111222029. The reversal of 21111222021 is 12022211112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21111222021 - 2¹ = 21111222019 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111222029) 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, 308655 + ... + 370796.

It is an arithmetic number, because the mean of its divisors is an integer number (3518881908).

Almost surely, 2^21111222021 is an apocalyptic number.

It is an amenable number.

21111222021 is a deficient number, since it is larger than the sum of its proper divisors (7039833243).

21111222021 is a wasteful number, since it uses less digits than its factorization.

21111222021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 689811.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21111222021 its reverse (12022211112), we get a palindrome (33133433133).

The spelling of 21111222021 in words is "twenty-one billion, one hundred eleven million, two hundred twenty-two thousand, twenty-one".