21012011021221 has 8 divisors (see below), whose sum is σ = 22922355312000. Its totient is φ = 19101693642240.

The previous prime is 21012011021189. The next prime is 21012011021227. The reversal of 21012011021221 is 12212011021012.

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

It is not a de Polignac number, because 21012011021221 - 2⁵ = 21012011021189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21012011021195 and 21012011021204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012011021227) 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, 5077821 + ... + 8234578.

It is an arithmetic number, because the mean of its divisors is an integer number (2865294414000).

Almost surely, 2^{21012011021221} is an apocalyptic number.

It is an amenable number.

21012011021221 is a deficient number, since it is larger than the sum of its proper divisors (1910344290779).

21012011021221 is a wasteful number, since it uses less digits than its factorization.

21012011021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13455899.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21012011021221 its reverse (12212011021012), we get a palindrome (33224022042233).

The spelling of 21012011021221 in words is "twenty-one trillion, twelve billion, eleven million, twenty-one thousand, two hundred twenty-one".