1921216201 has 2 divisors, whose sum is σ = 1921216202. Its totient is φ = 1921216200.

The previous prime is 1921216177. The next prime is 1921216229. The reversal of 1921216201 is 1026121291.

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., 1489574025 + 431642176 = 38595^2 + 20776^2 .

It is a cyclic number.

It is not a de Polignac number, because 1921216201 - 2¹¹ = 1921214153 is a prime.

It is not a weakly prime, because it can be changed into another prime (1921216301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 960608100 + 960608101.

It is an arithmetic number, because the mean of its divisors is an integer number (960608101).

Almost surely, 2^1921216201 is an apocalyptic number.

It is an amenable number.

1921216201 is a deficient number, since it is larger than the sum of its proper divisors (1).

1921216201 is an equidigital number, since it uses as much as digits as its factorization.

1921216201 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 1921216201 is about 43831.6803351183. The cubic root of 1921216201 is about 1243.1553788841.

Adding to 1921216201 its reverse (1026121291), we get a palindrome (2947337492).

The spelling of 1921216201 in words is "one billion, nine hundred twenty-one million, two hundred sixteen thousand, two hundred one".