21221455201 has 4 divisors (see below), whose sum is σ = 21906018304. Its totient is φ = 20536892100.

The previous prime is 21221455169. The next prime is 21221455207. The reversal of 21221455201 is 10255412212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21221455201 - 2⁵ = 21221455169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221455207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 342281505 + ... + 342281566.

It is an arithmetic number, because the mean of its divisors is an integer number (5476504576).

Almost surely, 2^21221455201 is an apocalyptic number.

It is an amenable number.

21221455201 is a deficient number, since it is larger than the sum of its proper divisors (684563103).

21221455201 is an equidigital number, since it uses as much as digits as its factorization.

21221455201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 684563102.

The product of its (nonzero) digits is 1600, while the sum is 25.

Adding to 21221455201 its reverse (10255412212), we get a palindrome (31476867413).

The spelling of 21221455201 in words is "twenty-one billion, two hundred twenty-one million, four hundred fifty-five thousand, two hundred one".