321405913 has 2 divisors, whose sum is σ = 321405914. Its totient is φ = 321405912.

The previous prime is 321405899. The next prime is 321405971. The reversal of 321405913 is 319504123.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 313042249 + 8363664 = 17693^2 + 2892^2 .

It is a cyclic number.

It is not a de Polignac number, because 321405913 - 2²¹ = 319308761 is a prime.

It is a super-2 number, since 2×321405913² = 206603521822727138, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (321400913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160702956 + 160702957.

It is an arithmetic number, because the mean of its divisors is an integer number (160702957).

Almost surely, 2^321405913 is an apocalyptic number.

It is an amenable number.

321405913 is a deficient number, since it is larger than the sum of its proper divisors (1).

321405913 is an equidigital number, since it uses as much as digits as its factorization.

321405913 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 321405913 is about 17927.7972154975. The cubic root of 321405913 is about 684.9906141822.

The spelling of 321405913 in words is "three hundred twenty-one million, four hundred five thousand, nine hundred thirteen".