156645221 has 4 divisors (see below), whose sum is σ = 156682944. Its totient is φ = 156607500.

The previous prime is 156645217. The next prime is 156645239. The reversal of 156645221 is 122546651.

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 156645221 - 2² = 156645217 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (156645121) 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, 11735 + ... + 21236.

It is an arithmetic number, because the mean of its divisors is an integer number (39170736).

Almost surely, 2^156645221 is an apocalyptic number.

It is an amenable number.

156645221 is a deficient number, since it is larger than the sum of its proper divisors (37723).

156645221 is an equidigital number, since it uses as much as digits as its factorization.

156645221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37722.

The product of its digits is 14400, while the sum is 32.

The square root of 156645221 is about 12515.7988558462. The cubic root of 156645221 is about 539.0624116687.

The spelling of 156645221 in words is "one hundred fifty-six million, six hundred forty-five thousand, two hundred twenty-one".