1721281633 has 2 divisors, whose sum is σ = 1721281634. Its totient is φ = 1721281632.

The previous prime is 1721281577. The next prime is 1721281643. The reversal of 1721281633 is 3361821271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1696451344 + 24830289 = 41188^2 + 4983^2 .

It is an emirp because it is prime and its reverse (3361821271) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1721281633 is a prime.

It is not a weakly prime, because it can be changed into another prime (1721281643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860640816 + 860640817.

It is an arithmetic number, because the mean of its divisors is an integer number (860640817).

Almost surely, 2^1721281633 is an apocalyptic number.

It is an amenable number.

1721281633 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721281633 is an equidigital number, since it uses as much as digits as its factorization.

1721281633 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 34.

The square root of 1721281633 is about 41488.3312872427. The cubic root of 1721281633 is about 1198.4428026080.

The spelling of 1721281633 in words is "one billion, seven hundred twenty-one million, two hundred eighty-one thousand, six hundred thirty-three".