263191997 has 8 divisors (see below), whose sum is σ = 270485880. Its totient is φ = 255939840.

The previous prime is 263191987. The next prime is 263192051. The reversal of 263191997 is 799191362.

It can be written as a sum of positive squares in 4 ways, for example, as 40018276 + 223173721 = 6326^2 + 14939^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 263191997 - 2⁸ = 263191741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (263191927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2579 + ... + 23087.

It is an arithmetic number, because the mean of its divisors is an integer number (33810735).

Almost surely, 2^263191997 is an apocalyptic number.

It is an amenable number.

263191997 is a deficient number, since it is larger than the sum of its proper divisors (7293883).

263191997 is a wasteful number, since it uses less digits than its factorization.

263191997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20863.

The product of its digits is 183708, while the sum is 47.

The square root of 263191997 is about 16223.1931813685. The cubic root of 263191997 is about 640.8517281378.

The spelling of 263191997 in words is "two hundred sixty-three million, one hundred ninety-one thousand, nine hundred ninety-seven".