21213403601221 has 4 divisors (see below), whose sum is σ = 22845203878252. Its totient is φ = 19581603324192.

The previous prime is 21213403601209. The next prime is 21213403601231. The reversal of 21213403601221 is 12210630431212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3285377378721 + 17928026222500 = 1812561^2 + 4234150^2 .

It is not a de Polignac number, because 21213403601221 - 2¹¹ = 21213403599173 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21213403601221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213403601231) 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, 815900138496 + ... + 815900138521.

It is an arithmetic number, because the mean of its divisors is an integer number (5711300969563).

Almost surely, 2^{21213403601221} is an apocalyptic number.

It is an amenable number.

21213403601221 is a deficient number, since it is larger than the sum of its proper divisors (1631800277031).

21213403601221 is a wasteful number, since it uses less digits than its factorization.

21213403601221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1631800277030.

The product of its (nonzero) digits is 3456, while the sum is 28.

The spelling of 21213403601221 in words is "twenty-one trillion, two hundred thirteen billion, four hundred three million, six hundred one thousand, two hundred twenty-one".