211920121 has 4 divisors (see below), whose sum is σ = 242194432. Its totient is φ = 181645812.

The previous prime is 211920109. The next prime is 211920151. The reversal of 211920121 is 121029112.

It is a happy number.

211920121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 211920121 - 2¹³ = 211911929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (211920101) 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, 15137145 + ... + 15137158.

It is an arithmetic number, because the mean of its divisors is an integer number (60548608).

Almost surely, 2^211920121 is an apocalyptic number.

It is an amenable number.

211920121 is a deficient number, since it is larger than the sum of its proper divisors (30274311).

211920121 is an equidigital number, since it uses as much as digits as its factorization.

211920121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30274310.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 211920121 is about 14557.4764640030. The cubic root of 211920121 is about 596.1982968908.

Adding to 211920121 its reverse (121029112), we get a palindrome (332949233).

The spelling of 211920121 in words is "two hundred eleven million, nine hundred twenty thousand, one hundred twenty-one".