26840640 has 112 divisors (see below), whose sum is σ = 86611968. Its totient is φ = 7041024.

The previous prime is 26840617. The next prime is 26840641. The reversal of 26840640 is 4604862.

26840640 = 570² + 571² + ... + 642².

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 26840598 and 26840607.

It is not an unprimeable number, because it can be changed into a prime (26840641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 69889 + ... + 70271.

Almost surely, 2^26840640 is an apocalyptic number.

26840640 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 26840640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43305984).

26840640 is an abundant number, since it is smaller than the sum of its proper divisors (59771328).

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

26840640 is a wasteful number, since it uses less digits than its factorization.

26840640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476 (or 466 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 26840640 is about 5180.7953057422. The cubic root of 26840640 is about 299.4086127475.

The spelling of 26840640 in words is "twenty-six million, eight hundred forty thousand, six hundred forty".