263640387 has 4 divisors (see below), whose sum is σ = 351520520. Its totient is φ = 175760256.

The previous prime is 263640383. The next prime is 263640397. The reversal of 263640387 is 783046362.

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

It is not a de Polignac number, because 263640387 - 2² = 263640383 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (263640383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43940062 + ... + 43940067.

It is an arithmetic number, because the mean of its divisors is an integer number (87880130).

Almost surely, 2^263640387 is an apocalyptic number.

263640387 is a deficient number, since it is larger than the sum of its proper divisors (87880133).

263640387 is an equidigital number, since it uses as much as digits as its factorization.

263640387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87880132.

The product of its (nonzero) digits is 145152, while the sum is 39.

The square root of 263640387 is about 16237.0067130614. The cubic root of 263640387 is about 641.2154530746.

The spelling of 263640387 in words is "two hundred sixty-three million, six hundred forty thousand, three hundred eighty-seven".