211221023 has 4 divisors (see below), whose sum is σ = 227468808. Its totient is φ = 194973240.

The previous prime is 211221013. The next prime is 211221037. The reversal of 211221023 is 320122112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 211221023 - 2²⁰ = 210172447 is a prime.

It is a super-2 number, since 2×211221023² = 89228641114333058, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 211220989 and 211221007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211221013) 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 3 ways as a sum of consecutive naturals, for example, 8123873 + ... + 8123898.

It is an arithmetic number, because the mean of its divisors is an integer number (56867202).

Almost surely, 2^211221023 is an apocalyptic number.

211221023 is a deficient number, since it is larger than the sum of its proper divisors (16247785).

211221023 is a wasteful number, since it uses less digits than its factorization.

211221023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16247784.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 211221023 is about 14533.4449804580. Note that the first 3 decimals coincide. The cubic root of 211221023 is about 595.5419800961.

Adding to 211221023 its reverse (320122112), we get a palindrome (531343135).

The spelling of 211221023 in words is "two hundred eleven million, two hundred twenty-one thousand, twenty-three".