312421721 has 2 divisors, whose sum is σ = 312421722. Its totient is φ = 312421720.

The previous prime is 312421717. The next prime is 312421729. The reversal of 312421721 is 127124213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 311875600 + 546121 = 17660^2 + 739^2 .

It is a cyclic number.

It is not a de Polignac number, because 312421721 - 2² = 312421717 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (312421729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 156210860 + 156210861.

It is an arithmetic number, because the mean of its divisors is an integer number (156210861).

Almost surely, 2^312421721 is an apocalyptic number.

It is an amenable number.

312421721 is a deficient number, since it is larger than the sum of its proper divisors (1).

312421721 is an equidigital number, since it uses as much as digits as its factorization.

312421721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 672, while the sum is 23.

The square root of 312421721 is about 17675.4553265255. The cubic root of 312421721 is about 678.5477375778.

Adding to 312421721 its reverse (127124213), we get a palindrome (439545934).

The spelling of 312421721 in words is "three hundred twelve million, four hundred twenty-one thousand, seven hundred twenty-one".