351720121 has 2 divisors, whose sum is σ = 351720122. Its totient is φ = 351720120.

The previous prime is 351720119. The next prime is 351720139. The reversal of 351720121 is 121027153.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 329967225 + 21752896 = 18165^2 + 4664^2 .

It is a cyclic number.

It is not a de Polignac number, because 351720121 - 2¹ = 351720119 is a prime.

Together with 351720119, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 351720092 and 351720101.

It is not a weakly prime, because it can be changed into another prime (351723121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 175860060 + 175860061.

It is an arithmetic number, because the mean of its divisors is an integer number (175860061).

Almost surely, 2^351720121 is an apocalyptic number.

It is an amenable number.

351720121 is a deficient number, since it is larger than the sum of its proper divisors (1).

351720121 is an equidigital number, since it uses as much as digits as its factorization.

351720121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 420, while the sum is 22.

The square root of 351720121 is about 18754.2027556492. The cubic root of 351720121 is about 705.8824829075.

Adding to 351720121 its reverse (121027153), we get a palindrome (472747274).

The spelling of 351720121 in words is "three hundred fifty-one million, seven hundred twenty thousand, one hundred twenty-one".