315127721 has 2 divisors, whose sum is σ = 315127722. Its totient is φ = 315127720.

The previous prime is 315127667. The next prime is 315127751. The reversal of 315127721 is 127721513.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 188677696 + 126450025 = 13736^2 + 11245^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-315127721 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (315127751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 157563860 + 157563861.

It is an arithmetic number, because the mean of its divisors is an integer number (157563861).

Almost surely, 2^315127721 is an apocalyptic number.

It is an amenable number.

315127721 is a deficient number, since it is larger than the sum of its proper divisors (1).

315127721 is an equidigital number, since it uses as much as digits as its factorization.

315127721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2940, while the sum is 29.

The square root of 315127721 is about 17751.8371161973. The cubic root of 315127721 is about 680.5011595343.

The spelling of 315127721 in words is "three hundred fifteen million, one hundred twenty-seven thousand, seven hundred twenty-one".