1681272696321 has 15 divisors (see below), whose sum is σ = 2511548250673. Its totient is φ = 1120840684380.

The previous prime is 1681272696277. The next prime is 1681272696329. The reversal of 1681272696321 is 1236962721861.

It is a happy number.

The square root of 1681272696321 is 1296639.

It is a perfect power (a square), and thus also a powerful number.

1681272696321 is a `hidden beast` number, since 168 + 1 + 2 + 72 + 6 + 96 + 321 = 666.

It is not a de Polignac number, because 1681272696321 - 2¹¹ = 1681272694273 is a prime.

It is a super-3 number, since 3×1681272696321³ (a number of 38 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1681272696329) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 11597716 + ... + 11741786.

Almost surely, 2^{1681272696321} is an apocalyptic number.

1681272696321 is the 1296639-th square number.

1681272696321 is the 648320-th centered octagonal number.

It is an amenable number.

1681272696321 is a deficient number, since it is larger than the sum of its proper divisors (830275554352).

1681272696321 is an frugal number, since it uses more digits than its factorization.

1681272696321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288154 (or 144074 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 54.

The spelling of 1681272696321 in words is "one trillion, six hundred eighty-one billion, two hundred seventy-two million, six hundred ninety-six thousand, three hundred twenty-one".