263243781773981 has 4 divisors (see below), whose sum is σ = 263293704741852. Its totient is φ = 263193858806112.

The previous prime is 263243781773977. The next prime is 263243781774013. The reversal of 263243781773981 is 189377187342362.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 192920043668356 + 70323738105625 = 13889566^2 + 8385925^2 .

It is a cyclic number.

It is not a de Polignac number, because 263243781773981 - 2² = 263243781773977 is a prime.

It is a super-2 number, since 2×263243781773981² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (263243781773281) 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, 24961476026 + ... + 24961486571.

It is an arithmetic number, because the mean of its divisors is an integer number (65823426185463).

Almost surely, 2^{263243781773981} is an apocalyptic number.

It is an amenable number.

263243781773981 is a deficient number, since it is larger than the sum of its proper divisors (49922967871).

263243781773981 is an equidigital number, since it uses as much as digits as its factorization.

263243781773981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49922967870.

The product of its digits is 512096256, while the sum is 71.

The spelling of 263243781773981 in words is "two hundred sixty-three trillion, two hundred forty-three billion, seven hundred eighty-one million, seven hundred seventy-three thousand, nine hundred eighty-one".