721215193 has 2 divisors, whose sum is σ = 721215194. Its totient is φ = 721215192.

The previous prime is 721215161. The next prime is 721215199. The reversal of 721215193 is 391512127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 486114304 + 235100889 = 22048^2 + 15333^2 .

It is an emirp because it is prime and its reverse (391512127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721215193 - 2⁵ = 721215161 is a prime.

It is a super-2 number, since 2×721215193² = 1040302709228054498, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (721215199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360607596 + 360607597.

It is an arithmetic number, because the mean of its divisors is an integer number (360607597).

Almost surely, 2^721215193 is an apocalyptic number.

It is an amenable number.

721215193 is a deficient number, since it is larger than the sum of its proper divisors (1).

721215193 is an equidigital number, since it uses as much as digits as its factorization.

721215193 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3780, while the sum is 31.

The square root of 721215193 is about 26855.4499683025. The cubic root of 721215193 is about 896.7849040165.

The spelling of 721215193 in words is "seven hundred twenty-one million, two hundred fifteen thousand, one hundred ninety-three".