263966640 has 160 divisors (see below), whose sum is σ = 948796416. Its totient is φ = 59458560.

The previous prime is 263966627. The next prime is 263966663. The reversal of 263966640 is 46669362.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 263966592 and 263966601.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 118174 + ... + 120386.

Almost surely, 2^263966640 is an apocalyptic number.

263966640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 263966640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (474398208).

263966640 is an abundant number, since it is smaller than the sum of its proper divisors (684829776).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

263966640 is a wasteful number, since it uses less digits than its factorization.

263966640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2307 (or 2301 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 42.

The square root of 263966640 is about 16247.0501938044. The cubic root of 263966640 is about 641.4798438141.

The spelling of 263966640 in words is "two hundred sixty-three million, nine hundred sixty-six thousand, six hundred forty".