21001202222221 has 8 divisors (see below), whose sum is σ = 22616781969824. Its totient is φ = 19385637139440.

The previous prime is 21001202222219. The next prime is 21001202222233. The reversal of 21001202222221 is 12222220210012.

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

It is not a de Polignac number, because 21001202222221 - 2¹ = 21001202222219 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001202222201) 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, 596691 + ... + 6508336.

It is an arithmetic number, because the mean of its divisors is an integer number (2827097746228).

Almost surely, 2^{21001202222221} is an apocalyptic number.

It is an amenable number.

21001202222221 is a deficient number, since it is larger than the sum of its proper divisors (1615579747603).

21001202222221 is a wasteful number, since it uses less digits than its factorization.

21001202222221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7332411.

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21001202222221 its reverse (12222220210012), we get a palindrome (33223422432233).

The spelling of 21001202222221 in words is "twenty-one trillion, one billion, two hundred two million, two hundred twenty-two thousand, two hundred twenty-one".