221787309249 has 135 divisors (see below), whose sum is σ = 374965950513. Its totient is φ = 130545399600.

The previous prime is 221787309217. The next prime is 221787309251. The reversal of 221787309249 is 942903787122.

It is a happy number.

The square root of 221787309249 is 470943.

It is a perfect power (a square), and thus also a powerful number.

221787309249 is a `hidden beast` number, since 2 + 2 + 17 + 87 + 309 + 249 = 666.

It is not a de Polignac number, because 221787309249 - 2⁵ = 221787309217 is a prime.

It is a super-2 number, since 2×221787309249² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221787309195 and 221787309204.

It is not an unprimeable number, because it can be changed into a prime (221787309209) by changing a digit.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 3123764884 + ... + 3123764954.

Almost surely, 2^221787309249 is an apocalyptic number.

221787309249 is the 470943-rd square number.

221787309249 is the 235472-nd centered octagonal number.

It is an amenable number.

221787309249 is a deficient number, since it is larger than the sum of its proper divisors (153178641264).

221787309249 is an frugal number, since it uses more digits than its factorization.

221787309249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 310 (or 152 counting only the distinct ones).

The product of its (nonzero) digits is 3048192, while the sum is 54.

The spelling of 221787309249 in words is "two hundred twenty-one billion, seven hundred eighty-seven million, three hundred nine thousand, two hundred forty-nine".