156221545 has 4 divisors (see below), whose sum is σ = 187465860. Its totient is φ = 124977232.

The previous prime is 156221531. The next prime is 156221573. The reversal of 156221545 is 545122651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 545122651 = 1013 ⋅538127.

It can be written as a sum of positive squares in 2 ways, for example, as 46621584 + 109599961 = 6828^2 + 10469^2 .

It is a cyclic number.

It is not a de Polignac number, because 156221545 - 2⁹ = 156221033 is a prime.

It is a super-2 number, since 2×156221545² = 48810342244374050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 15622150 + ... + 15622159.

It is an arithmetic number, because the mean of its divisors is an integer number (46866465).

Almost surely, 2^156221545 is an apocalyptic number.

It is an amenable number.

156221545 is a deficient number, since it is larger than the sum of its proper divisors (31244315).

156221545 is an equidigital number, since it uses as much as digits as its factorization.

156221545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31244314.

The product of its digits is 12000, while the sum is 31.

The square root of 156221545 is about 12498.8617481753. The cubic root of 156221545 is about 538.5759748222.

The spelling of 156221545 in words is "one hundred fifty-six million, two hundred twenty-one thousand, five hundred forty-five".