211221401 has 4 divisors (see below), whose sum is σ = 213312804. Its totient is φ = 209130000.

The previous prime is 211221371. The next prime is 211221421. The reversal of 211221401 is 104122112.

It is a happy number.

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 182277001 + 28944400 = 13501^2 + 5380^2 .

It is a cyclic number.

It is not a de Polignac number, because 211221401 - 2¹⁸ = 210959257 is a prime.

It is a super-2 number, since 2×211221401² = 89228960480805602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (211221421) 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, 1045550 + ... + 1045751.

It is an arithmetic number, because the mean of its divisors is an integer number (53328201).

Almost surely, 2^211221401 is an apocalyptic number.

It is an amenable number.

211221401 is a deficient number, since it is larger than the sum of its proper divisors (2091403).

211221401 is a wasteful number, since it uses less digits than its factorization.

211221401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2091402.

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 211221401 is about 14533.4579849394. The cubic root of 211221401 is about 595.5423353555.

Adding to 211221401 its reverse (104122112), we get a palindrome (315343513).

The spelling of 211221401 in words is "two hundred eleven million, two hundred twenty-one thousand, four hundred one".