26688721 has 4 divisors (see below), whose sum is σ = 26838000. Its totient is φ = 26539444.

The previous prime is 26688703. The next prime is 26688743. The reversal of 26688721 is 12788662.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-26688721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (26688751) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 74371 + ... + 74728.

It is an arithmetic number, because the mean of its divisors is an integer number (6709500).

Almost surely, 2^26688721 is an apocalyptic number.

It is an amenable number.

26688721 is a deficient number, since it is larger than the sum of its proper divisors (149279).

26688721 is a wasteful number, since it uses less digits than its factorization.

26688721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149278.

The product of its digits is 64512, while the sum is 40.

The square root of 26688721 is about 5166.1127552542. The cubic root of 26688721 is about 298.8426557372.

The spelling of 26688721 in words is "twenty-six million, six hundred eighty-eight thousand, seven hundred twenty-one".