361215721 has 2 divisors, whose sum is σ = 361215722. Its totient is φ = 361215720.

The previous prime is 361215697. The next prime is 361215731. The reversal of 361215721 is 127512163.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 275394025 + 85821696 = 16595^2 + 9264^2 .

It is an emirp because it is prime and its reverse (127512163) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 361215721 - 2¹⁹ = 360691433 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 361215721.

It is not a weakly prime, because it can be changed into another prime (361215731) 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, 180607860 + 180607861.

It is an arithmetic number, because the mean of its divisors is an integer number (180607861).

Almost surely, 2^361215721 is an apocalyptic number.

It is an amenable number.

361215721 is a deficient number, since it is larger than the sum of its proper divisors (1).

361215721 is an equidigital number, since it uses as much as digits as its factorization.

361215721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2520, while the sum is 28.

The square root of 361215721 is about 19005.6760205997. The cubic root of 361215721 is about 712.1785370825.

Adding to 361215721 its reverse (127512163), we get a palindrome (488727884).

The spelling of 361215721 in words is "three hundred sixty-one million, two hundred fifteen thousand, seven hundred twenty-one".