21012022221 has 8 divisors (see below), whose sum is σ = 28172544480. Its totient is φ = 13929757392.

The previous prime is 21012022201. The next prime is 21012022243. The reversal of 21012022221 is 12222021012.

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

It is not a de Polignac number, because 21012022221 - 2⁵ = 21012022189 is a prime.

It is a super-3 number, since 3×21012022221³ (a number of 32 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21012022221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012022201) 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, 19563730 + ... + 19564803.

It is an arithmetic number, because the mean of its divisors is an integer number (3521568060).

Almost surely, 2^21012022221 is an apocalyptic number.

It is an amenable number.

21012022221 is a deficient number, since it is larger than the sum of its proper divisors (7160522259).

21012022221 is a wasteful number, since it uses less digits than its factorization.

21012022221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39128715.

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21012022221 its reverse (12222021012), we get a palindrome (33234043233).

The spelling of 21012022221 in words is "twenty-one billion, twelve million, twenty-two thousand, two hundred twenty-one".