5718721 has 8 divisors (see below), whose sum is σ = 5920488. Its totient is φ = 5520000.

The previous prime is 5718709. The next prime is 5718737. The reversal of 5718721 is 1278175.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 790321 + 4928400 = 889^2 + 2220^2 .

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

It is a 4-Lehmer number, since φ(5718721) divides (5718721-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 5718721 - 2⁷ = 5718593 is a prime.

It is a deceptive number, since it divides R_5718720.

It is a Duffinian number.

5718721 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5718701) 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, 3451 + ... + 4831.

It is an arithmetic number, because the mean of its divisors is an integer number (740061).

Almost surely, 2^5718721 is an apocalyptic number.

5718721 is the 1381-st octagonal number.

It is an amenable number.

5718721 is a deficient number, since it is larger than the sum of its proper divisors (201767).

5718721 is a wasteful number, since it uses less digits than its factorization.

5718721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1523.

The product of its digits is 3920, while the sum is 31.

The square root of 5718721 is about 2391.3847452888. The cubic root of 5718721 is about 178.8269500956.

The spelling of 5718721 in words is "five million, seven hundred eighteen thousand, seven hundred twenty-one".