221121101021 has 4 divisors (see below), whose sum is σ = 221178138972. Its totient is φ = 221064063072.

The previous prime is 221121101011. The next prime is 221121101057. The reversal of 221121101021 is 120101121122.

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 165373168921 + 55747932100 = 406661^2 + 236110^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221121101021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221121100987 and 221121101005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221121101011) 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, 28513160 + ... + 28520913.

It is an arithmetic number, because the mean of its divisors is an integer number (55294534743).

Almost surely, 2^221121101021 is an apocalyptic number.

It is an amenable number.

221121101021 is a deficient number, since it is larger than the sum of its proper divisors (57037951).

221121101021 is an equidigital number, since it uses as much as digits as its factorization.

221121101021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57037950.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 221121101021 its reverse (120101121122), we get a palindrome (341222222143).

The spelling of 221121101021 in words is "two hundred twenty-one billion, one hundred twenty-one million, one hundred one thousand, twenty-one".