1321575305721 has 16 divisors (see below), whose sum is σ = 1950982272768. Its totient is φ = 789000181200.

The previous prime is 1321575305711. The next prime is 1321575305747. The reversal of 1321575305721 is 1275035751231.

It is not a de Polignac number, because 1321575305721 - 2¹⁷ = 1321575174649 is a prime.

It is a super-2 number, since 2×1321575305721² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1321575305711) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 298861495 + ... + 298865916.

It is an arithmetic number, because the mean of its divisors is an integer number (121936392048).

Almost surely, 2^{1321575305721} is an apocalyptic number.

1321575305721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1321575305721 is a deficient number, since it is larger than the sum of its proper divisors (629406967047).

1321575305721 is a wasteful number, since it uses less digits than its factorization.

1321575305721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 597727492.

The product of its (nonzero) digits is 220500, while the sum is 42.

The spelling of 1321575305721 in words is "one trillion, three hundred twenty-one billion, five hundred seventy-five million, three hundred five thousand, seven hundred twenty-one".