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1217561221 is a prime number
BaseRepresentation
bin100100010010010…
…1000001010000101
310010212001112000001
41020210220022011
54443143424341
6320452321301
742113046112
oct11044501205
93125045001
101217561221
11575310848
1229b913231
13165332836
14b79c1909
1571d58d31
hex48928285

1217561221 has 2 divisors, whose sum is σ = 1217561222. Its totient is φ = 1217561220.

The previous prime is 1217561167. The next prime is 1217561237. The reversal of 1217561221 is 1221657121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1081488996 + 136072225 = 32886^2 + 11665^2 .

It is a cyclic number.

It is not a de Polignac number, because 1217561221 - 211 = 1217559173 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1217561221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1217561621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608780610 + 608780611.

It is an arithmetic number, because the mean of its divisors is an integer number (608780611).

Almost surely, 21217561221 is an apocalyptic number.

It is an amenable number.

1217561221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1217561221 is an equidigital number, since it uses as much as digits as its factorization.

1217561221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1680, while the sum is 28.

The square root of 1217561221 is about 34893.5699090821. The cubic root of 1217561221 is about 1067.8172585095.

The spelling of 1217561221 in words is "one billion, two hundred seventeen million, five hundred sixty-one thousand, two hundred twenty-one".