721317229 has 2 divisors, whose sum is σ = 721317230. Its totient is φ = 721317228.

The previous prime is 721317209. The next prime is 721317239. The reversal of 721317229 is 922713127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 708997129 + 12320100 = 26627^2 + 3510^2 .

It is a cyclic number.

It is not a de Polignac number, because 721317229 - 2¹¹ = 721315181 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 721317194 and 721317203.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721317209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360658614 + 360658615.

It is an arithmetic number, because the mean of its divisors is an integer number (360658615).

Almost surely, 2^721317229 is an apocalyptic number.

It is an amenable number.

721317229 is a deficient number, since it is larger than the sum of its proper divisors (1).

721317229 is an equidigital number, since it uses as much as digits as its factorization.

721317229 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10584, while the sum is 34.

The square root of 721317229 is about 26857.3496272436. The cubic root of 721317229 is about 896.8271937660.

It can be divided in two parts, 7213 and 17229, that added together give a palindrome (24442).

The spelling of 721317229 in words is "seven hundred twenty-one million, three hundred seventeen thousand, two hundred twenty-nine".