1997351878729 has 9 divisors (see below), whose sum is σ = 2108036832813. Its totient is φ = 1892202656652.

The previous prime is 1997351878703. The next prime is 1997351878741. The reversal of 1997351878729 is 9278781537991.

The square root of 1997351878729 is 1413277.

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

It is not a de Polignac number, because 1997351878729 - 2¹³ = 1997351870537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1997351878789) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 26815072 + ... + 26889454.

It is an arithmetic number, because the mean of its divisors is an integer number (234226314757).

Almost surely, 2^{1997351878729} is an apocalyptic number.

1997351878729 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1997351878729 is the 1413277-th square number.

1997351878729 is the 706639-th centered octagonal number.

It is an amenable number.

1997351878729 is a deficient number, since it is larger than the sum of its proper divisors (110684954084).

1997351878729 is an frugal number, since it uses more digits than its factorization.

1997351878729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148804 (or 74402 counting only the distinct ones).

The product of its digits is 480090240, while the sum is 76.

The spelling of 1997351878729 in words is "one trillion, nine hundred ninety-seven billion, three hundred fifty-one million, eight hundred seventy-eight thousand, seven hundred twenty-nine".