221020101 has 6 divisors (see below), whose sum is σ = 319251270. Its totient is φ = 147346728.

The previous prime is 221020099. The next prime is 221020127. The reversal of 221020101 is 101020122.

It can be written as a sum of positive squares in only one way, i.e., 213452100 + 7568001 = 14610^2 + 2751^2 .

It is not a de Polignac number, because 221020101 - 2¹ = 221020099 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 24557789 = 221020101 / (2 + 2 + 1 + 0 + 2 + 0 + 1 + 0 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221020001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12278886 + ... + 12278903.

It is an arithmetic number, because the mean of its divisors is an integer number (53208545).

Almost surely, 2^221020101 is an apocalyptic number.

It is an amenable number.

221020101 is a deficient number, since it is larger than the sum of its proper divisors (98231169).

221020101 is a wasteful number, since it uses less digits than its factorization.

221020101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24557795 (or 24557792 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 221020101 is about 14866.7448017379. The cubic root of 221020101 is about 604.6126892887.

Adding to 221020101 its reverse (101020122), we get a palindrome (322040223).

The spelling of 221020101 in words is "two hundred twenty-one million, twenty thousand, one hundred one".