20101021221 has 16 divisors (see below), whose sum is σ = 28386716544. Its totient is φ = 12608492544.

The previous prime is 20101021211. The next prime is 20101021223. The reversal of 20101021221 is 12212010102.

It is not a de Polignac number, because 20101021221 - 2⁷ = 20101021093 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20101021197 and 20101021206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20101021223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 109480 + ... + 228446.

It is an arithmetic number, because the mean of its divisors is an integer number (1774169784).

Almost surely, 2^20101021221 is an apocalyptic number.

It is an amenable number.

20101021221 is a deficient number, since it is larger than the sum of its proper divisors (8285695323).

20101021221 is a wasteful number, since it uses less digits than its factorization.

20101021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122300.

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

Adding to 20101021221 its reverse (12212010102), we get a palindrome (32313031323).

It can be divided in two parts, 2010102 and 1221, that multiplied together give a palindrome (2454334542).

The spelling of 20101021221 in words is "twenty billion, one hundred one million, twenty-one thousand, two hundred twenty-one".