1320506666721 has 40 divisors (see below), whose sum is σ = 2152568614944. Its totient is φ = 800072095680.

The previous prime is 1320506666639. The next prime is 1320506666813. The reversal of 1320506666721 is 1276666050231.

It is not a de Polignac number, because 1320506666721 - 2¹⁰ = 1320506665697 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1320506666021) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 2842950 + ... + 3274656.

Almost surely, 2^{1320506666721} is an apocalyptic number.

1320506666721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1320506666721 is a deficient number, since it is larger than the sum of its proper divisors (832061948223).

1320506666721 is a wasteful number, since it uses less digits than its factorization.

1320506666721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 435163 (or 435154 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 45.

The spelling of 1320506666721 in words is "one trillion, three hundred twenty billion, five hundred six million, six hundred sixty-six thousand, seven hundred twenty-one".