221001001221 has 128 divisors (see below), whose sum is σ = 407029948416. Its totient is φ = 102933089280.

The previous prime is 221001001187. The next prime is 221001001229. The reversal of 221001001221 is 122100100122.

It is not a de Polignac number, because 221001001221 - 2¹³ = 221000993029 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221001001197 and 221001001206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221001001229) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 82554135 + ... + 82556811.

It is an arithmetic number, because the mean of its divisors is an integer number (3179921472).

Almost surely, 2^221001001221 is an apocalyptic number.

221001001221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

221001001221 is a deficient number, since it is larger than the sum of its proper divisors (186028947195).

221001001221 is a wasteful number, since it uses less digits than its factorization.

221001001221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3491.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 221001001221 its reverse (122100100122), we get a palindrome (343101101343).

The spelling of 221001001221 in words is "two hundred twenty-one billion, one million, one thousand, two hundred twenty-one".