156211221 has 8 divisors (see below), whose sum is σ = 212713344. Its totient is φ = 101924960.

The previous prime is 156211199. The next prime is 156211241. The reversal of 156211221 is 122112651.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 156211221 - 2⁷ = 156211093 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (156211241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 553800 + ... + 554081.

It is an arithmetic number, because the mean of its divisors is an integer number (26589168).

Almost surely, 2^156211221 is an apocalyptic number.

It is an amenable number.

156211221 is a deficient number, since it is larger than the sum of its proper divisors (56502123).

156211221 is a wasteful number, since it uses less digits than its factorization.

156211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1107931.

The product of its digits is 240, while the sum is 21.

The square root of 156211221 is about 12498.4487437442. The cubic root of 156211221 is about 538.5641105157.

Adding to 156211221 its reverse (122112651), we get a palindrome (278323872).

The spelling of 156211221 in words is "one hundred fifty-six million, two hundred eleven thousand, two hundred twenty-one".