826640640 has 720 divisors, whose sum is σ = 3632694912. Its totient is φ = 175177728.

The previous prime is 826640603. The next prime is 826640641. The reversal of 826640640 is 46046628.

It is a happy number.

826640640 is a `hidden beast` number, since 8 + 2 + 6 + 6 + 4 + 0 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 826640595 and 826640604.

It is not an unprimeable number, because it can be changed into a prime (826640641) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 12337887 + ... + 12337953.

Almost surely, 2^826640640 is an apocalyptic number.

826640640 is a gapful number since it is divisible by the number (80) 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 826640640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1816347456).

826640640 is an abundant number, since it is smaller than the sum of its proper divisors (2806054272).

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

826640640 is a wasteful number, since it uses less digits than its factorization.

826640640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The square root of 826640640 is about 28751.3589244056. The cubic root of 826640640 is about 938.5100282417.

The spelling of 826640640 in words is "eight hundred twenty-six million, six hundred forty thousand, six hundred forty".