26720721 has 12 divisors (see below), whose sum is σ = 38732148. Its totient is φ = 17751264.

The previous prime is 26720717. The next prime is 26720741. The reversal of 26720721 is 12702762.

It can be written as a sum of positive squares in 2 ways, for example, as 23619600 + 3101121 = 4860^2 + 1761^2 .

It is not a de Polignac number, because 26720721 - 2² = 26720717 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26720741) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2430 + ... + 7703.

It is an arithmetic number, because the mean of its divisors is an integer number (3227679).

Almost surely, 2^26720721 is an apocalyptic number.

It is an amenable number.

26720721 is a deficient number, since it is larger than the sum of its proper divisors (12011427).

26720721 is a wasteful number, since it uses less digits than its factorization.

26720721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10432 (or 10429 counting only the distinct ones).

The product of its (nonzero) digits is 2352, while the sum is 27.

The square root of 26720721 is about 5169.2089336764. The cubic root of 26720721 is about 298.9620463154.

The spelling of 26720721 in words is "twenty-six million, seven hundred twenty thousand, seven hundred twenty-one".