221400213021 has 12 divisors (see below), whose sum is σ = 344400331548. Its totient is φ = 136246284864.

The previous prime is 221400213019. The next prime is 221400213061. The reversal of 221400213021 is 120312004122.

It is a happy number.

221400213021 is a `hidden beast` number, since 221 + 400 + 21 + 3 + 0 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 95967365796 + 125432847225 = 309786^2 + 354165^2 .

It is not a de Polignac number, because 221400213021 - 2¹ = 221400213019 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 221400212985 and 221400213003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221400213061) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 946154640 + ... + 946154873.

It is an arithmetic number, because the mean of its divisors is an integer number (28700027629).

Almost surely, 2^221400213021 is an apocalyptic number.

It is an amenable number.

221400213021 is a deficient number, since it is larger than the sum of its proper divisors (123000118527).

221400213021 is a wasteful number, since it uses less digits than its factorization.

221400213021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1892309532 (or 1892309529 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 221400213021 its reverse (120312004122), we get a palindrome (341712217143).

The spelling of 221400213021 in words is "two hundred twenty-one billion, four hundred million, two hundred thirteen thousand, twenty-one".