26640509 has 8 divisors (see below), whose sum is σ = 31770240. Its totient is φ = 21841776.

The previous prime is 26640487. The next prime is 26640511. The reversal of 26640509 is 90504662.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-26640509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26640569) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82574 + ... + 82895.

It is an arithmetic number, because the mean of its divisors is an integer number (3971280).

Almost surely, 2^26640509 is an apocalyptic number.

It is an amenable number.

26640509 is a deficient number, since it is larger than the sum of its proper divisors (5129731).

26640509 is a wasteful number, since it uses less digits than its factorization.

26640509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165499.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 26640509 is about 5161.4444683635. Note that the first 4 decimals coincide. The cubic root of 26640509 is about 298.6625985697.

The spelling of 26640509 in words is "twenty-six million, six hundred forty thousand, five hundred nine".