211220129 has 4 divisors (see below), whose sum is σ = 211249584. Its totient is φ = 211190676.

The previous prime is 211220123. The next prime is 211220153. The reversal of 211220129 is 921022112.

It is a happy number.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211220129 is a prime.

It is a super-2 number, since 2×211220129² = 89227885789553282, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 211220129.

It is not an unprimeable number, because it can be changed into a prime (211220123) 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, 3794 + ... + 20900.

It is an arithmetic number, because the mean of its divisors is an integer number (52812396).

Almost surely, 2^211220129 is an apocalyptic number.

It is an amenable number.

211220129 is a deficient number, since it is larger than the sum of its proper divisors (29455).

211220129 is a wasteful number, since it uses less digits than its factorization.

211220129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29454.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 211220129 is about 14533.4142237810. The cubic root of 211220129 is about 595.5411398778.

The spelling of 211220129 in words is "two hundred eleven million, two hundred twenty thousand, one hundred twenty-nine".