210221111100021 has 16 divisors (see below), whose sum is σ = 320337690230784. Its totient is φ = 120126064563504.

The previous prime is 210221111099977. The next prime is 210221111100029. The reversal of 210221111100021 is 120001111122012.

It is a happy number.

It is not a de Polignac number, because 210221111100021 - 2⁹ = 210221111099509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210221111100029) 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, 2618661 + ... + 20671226.

It is an arithmetic number, because the mean of its divisors is an integer number (20021105639424).

Almost surely, 2^{210221111100021} is an apocalyptic number.

210221111100021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

210221111100021 is a deficient number, since it is larger than the sum of its proper divisors (110116579130763).

210221111100021 is a wasteful number, since it uses less digits than its factorization.

210221111100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23719720.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 210221111100021 its reverse (120001111122012), we get a palindrome (330222222222033).

The spelling of 210221111100021 in words is "two hundred ten trillion, two hundred twenty-one billion, one hundred eleven million, one hundred thousand, twenty-one".