55038721 has 8 divisors (see below), whose sum is σ = 56680040. Its totient is φ = 53405568.

The previous prime is 55038719. The next prime is 55038749. The reversal of 55038721 is 12783055.

It can be written as a sum of positive squares in 4 ways, for example, as 15210000 + 39828721 = 3900^2 + 6311^2 .

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 55038721 - 2¹ = 55038719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55038121) 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, 13315 + ... + 16951.

It is an arithmetic number, because the mean of its divisors is an integer number (7085005).

Almost surely, 2^55038721 is an apocalyptic number.

It is an amenable number.

55038721 is a deficient number, since it is larger than the sum of its proper divisors (1641319).

55038721 is a wasteful number, since it uses less digits than its factorization.

55038721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4083.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 55038721 is about 7418.8085970727. The cubic root of 55038721 is about 380.3844700635.

The spelling of 55038721 in words is "fifty-five million, thirty-eight thousand, seven hundred twenty-one".