1398403216681 has 27 divisors (see below), whose sum is σ = 1492154680023. Its totient is φ = 1310350031280.

The previous prime is 1398403216649. The next prime is 1398403216697. The reversal of 1398403216681 is 1866123048931.

The square root of 1398403216681 is 1182541.

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

It can be written as a sum of positive squares in only one way, i.e., 974680333081 + 423722883600 = 987259^2 + 650940^2 .

It is not a de Polignac number, because 1398403216681 - 2⁵ = 1398403216649 is a prime.

It is a super-2 number, since 2×1398403216681² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1398403216621) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2449042126 + ... + 2449042696.

It is an arithmetic number, because the mean of its divisors is an integer number (55264988149).

Almost surely, 2^{1398403216681} is an apocalyptic number.

1398403216681 is the 1182541-st square number.

1398403216681 is the 591271-st centered octagonal number.

It is an amenable number.

1398403216681 is a deficient number, since it is larger than the sum of its proper divisors (93751463342).

1398403216681 is an frugal number, since it uses more digits than its factorization.

1398403216681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1398 (or 699 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 52.

The spelling of 1398403216681 in words is "one trillion, three hundred ninety-eight billion, four hundred three million, two hundred sixteen thousand, six hundred eighty-one".