721885321 has 2 divisors, whose sum is σ = 721885322. Its totient is φ = 721885320.

The previous prime is 721885303. The next prime is 721885343. The reversal of 721885321 is 123588127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 502252921 + 219632400 = 22411^2 + 14820^2 .

It is a cyclic number.

It is not a de Polignac number, because 721885321 - 2¹¹ = 721883273 is a prime.

It is a super-2 number, since 2×721885321² = 1042236833350546082, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (721885301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360942660 + 360942661.

It is an arithmetic number, because the mean of its divisors is an integer number (360942661).

Almost surely, 2^721885321 is an apocalyptic number.

It is an amenable number.

721885321 is a deficient number, since it is larger than the sum of its proper divisors (1).

721885321 is an equidigital number, since it uses as much as digits as its factorization.

721885321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26880, while the sum is 37.

The square root of 721885321 is about 26867.9236451200. The cubic root of 721885321 is about 897.0625717849.

The spelling of 721885321 in words is "seven hundred twenty-one million, eight hundred eighty-five thousand, three hundred twenty-one".