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161559991 is a prime number
BaseRepresentation
bin10011010000100…
…11010110110111
3102021000002122101
421220103112313
5312324404431
624010442531
74001144245
oct1150232667
9367002571
10161559991
118321845a
1246133447
1327618838
1417657795
15e2b4961
hex9a135b7

161559991 has 2 divisors, whose sum is σ = 161559992. Its totient is φ = 161559990.

The previous prime is 161559971. The next prime is 161560031. The reversal of 161559991 is 199955161.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 161559991 - 27 = 161559863 is a prime.

It is a super-2 number, since 2×1615599912 = 52203261383840162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161559971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80779995 + 80779996.

It is an arithmetic number, because the mean of its divisors is an integer number (80779996).

Almost surely, 2161559991 is an apocalyptic number.

161559991 is a deficient number, since it is larger than the sum of its proper divisors (1).

161559991 is an equidigital number, since it uses as much as digits as its factorization.

161559991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 109350, while the sum is 46.

The square root of 161559991 is about 12710.6251223140. The cubic root of 161559991 is about 544.6421813089.

The spelling of 161559991 in words is "one hundred sixty-one million, five hundred fifty-nine thousand, nine hundred ninety-one".