264778640 has 80 divisors (see below), whose sum is σ = 714156672. Its totient is φ = 89413632.

The previous prime is 264778639. The next prime is 264778693. The reversal of 264778640 is 46877462.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 264778591 and 264778600.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33992 + ... + 41048.

Almost surely, 2^264778640 is an apocalyptic number.

264778640 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 264778640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (357078336).

264778640 is an abundant number, since it is smaller than the sum of its proper divisors (449378032).

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

264778640 is a wasteful number, since it uses less digits than its factorization.

264778640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7144 (or 7138 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 44.

The square root of 264778640 is about 16272.0201573130. The cubic root of 264778640 is about 642.1369324541.

The spelling of 264778640 in words is "two hundred sixty-four million, seven hundred seventy-eight thousand, six hundred forty".