55806721 has 8 divisors (see below), whose sum is σ = 57314304. Its totient is φ = 54316080.

The previous prime is 55806703. The next prime is 55806811. The reversal of 55806721 is 12760855.

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

It is a cyclic number.

It is not a de Polignac number, because 55806721 - 2⁷ = 55806593 is a prime.

It is a super-2 number, since 2×55806721² = 6228780217543682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55800721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2586 + ... + 10876.

It is an arithmetic number, because the mean of its divisors is an integer number (7164288).

Almost surely, 2^55806721 is an apocalyptic number.

It is an amenable number.

55806721 is a deficient number, since it is larger than the sum of its proper divisors (1507583).

55806721 is a wasteful number, since it uses less digits than its factorization.

55806721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8471.

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 55806721 is about 7470.3896150067. The cubic root of 55806721 is about 382.1455751184.

The spelling of 55806721 in words is "fifty-five million, eight hundred six thousand, seven hundred twenty-one".