993257781601 has 4 divisors (see below), whose sum is σ = 993260083204. Its totient is φ = 993255480000.

The previous prime is 993257781589. The next prime is 993257781667. The reversal of 993257781601 is 106187752399.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 106187752399 = 113 ⋅939714623.

It can be written as a sum of positive squares in 2 ways, for example, as 542802036001 + 450455745600 = 736751^2 + 671160^2 .

It is a 3-Lehmer number, since φ(993257781601) divides (993257781601-1)³.

It is a cyclic number.

It is not a de Polignac number, because 993257781601 - 2¹⁷ = 993257650529 is a prime.

It is a super-2 number, since 2×993257781601² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (993257781671) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 287700 + ... + 1438501.

It is an arithmetic number, because the mean of its divisors is an integer number (248315020801).

It is a Poulet number, since it divides 2^993257781600-1.

Almost surely, 2^993257781601 is an apocalyptic number.

993257781601 is the 575401-st octagonal number.

It is an amenable number.

993257781601 is a deficient number, since it is larger than the sum of its proper divisors (2301603).

993257781601 is a wasteful number, since it uses less digits than its factorization.

993257781601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2301602.

The product of its (nonzero) digits is 5715360, while the sum is 58.

The spelling of 993257781601 in words is "nine hundred ninety-three billion, two hundred fifty-seven million, seven hundred eighty-one thousand, six hundred one".