211221097 has 4 divisors (see below), whose sum is σ = 211737940. Its totient is φ = 210704256.

The previous prime is 211221091. The next prime is 211221169. The reversal of 211221097 is 790122112.

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

It can be written as a sum of positive squares in 2 ways, for example, as 161391616 + 49829481 = 12704^2 + 7059^2 .

It is a cyclic number.

It is not a de Polignac number, because 211221097 - 2⁷ = 211220969 is a prime.

It is a super-2 number, since 2×211221097² = 89228703635766818, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (211221091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 257808 + ... + 258625.

It is an arithmetic number, because the mean of its divisors is an integer number (52934485).

Almost surely, 2^211221097 is an apocalyptic number.

It is an amenable number.

211221097 is a deficient number, since it is larger than the sum of its proper divisors (516843).

211221097 is an equidigital number, since it uses as much as digits as its factorization.

211221097 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516842.

The product of its (nonzero) digits is 504, while the sum is 25.

The square root of 211221097 is about 14533.4475263098. The cubic root of 211221097 is about 595.5420496443.

The spelling of 211221097 in words is "two hundred eleven million, two hundred twenty-one thousand, ninety-seven".