21221220201 has 8 divisors (see below), whose sum is σ = 28298925984. Its totient is φ = 14145497280.

The previous prime is 21221220199. The next prime is 21221220203. The reversal of 21221220201 is 10202212212.

It is an interprime number because it is at equal distance from previous prime (21221220199) and next prime (21221220203).

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

It is not a de Polignac number, because 21221220201 - 2¹ = 21221220199 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21221220203) 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, 470560 + ... + 513681.

It is an arithmetic number, because the mean of its divisors is an integer number (3537365748).

Almost surely, 2^21221220201 is an apocalyptic number.

It is an amenable number.

21221220201 is a deficient number, since it is larger than the sum of its proper divisors (7077705783).

21221220201 is an equidigital number, since it uses as much as digits as its factorization.

21221220201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 991431.

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

Adding to 21221220201 its reverse (10202212212), we get a palindrome (31423432413).

The spelling of 21221220201 in words is "twenty-one billion, two hundred twenty-one million, two hundred twenty thousand, two hundred one".