211221023021 has 2 divisors, whose sum is σ = 211221023022. Its totient is φ = 211221023020.

The previous prime is 211221022967. The next prime is 211221023047. The reversal of 211221023021 is 120320122112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 196528189225 + 14692833796 = 443315^2 + 121214^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211221023021 is a prime.

It is a super-2 number, since 2×211221023021² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211221023051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105610511510 + 105610511511.

It is an arithmetic number, because the mean of its divisors is an integer number (105610511511).

Almost surely, 2^211221023021 is an apocalyptic number.

It is an amenable number.

211221023021 is a deficient number, since it is larger than the sum of its proper divisors (1).

211221023021 is an equidigital number, since it uses as much as digits as its factorization.

211221023021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 211221023021 its reverse (120320122112), we get a palindrome (331541145133).

Subtracting from 211221023021 its reverse (120320122112), we obtain a palindrome (90900900909).

The spelling of 211221023021 in words is "two hundred eleven billion, two hundred twenty-one million, twenty-three thousand, twenty-one".