55221012010721 has 4 divisors (see below), whose sum is σ = 56567865962244. Its totient is φ = 53874158059200.

The previous prime is 55221012010711. The next prime is 55221012010739. The reversal of 55221012010721 is 12701021012255.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16911101760721 + 38309910250000 = 4112311^2 + 6189500^2 .

It is a cyclic number.

It is not a de Polignac number, because 55221012010721 - 2¹⁸ = 55221011748577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55221012010711) 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, 673426975700 + ... + 673426975781.

It is an arithmetic number, because the mean of its divisors is an integer number (14141966490561).

Almost surely, 2^{55221012010721} is an apocalyptic number.

It is an amenable number.

55221012010721 is a deficient number, since it is larger than the sum of its proper divisors (1346853951523).

55221012010721 is a wasteful number, since it uses less digits than its factorization.

55221012010721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1346853951522.

The product of its (nonzero) digits is 2800, while the sum is 29.

Adding to 55221012010721 its reverse (12701021012255), we get a palindrome (67922033022976).

The spelling of 55221012010721 in words is "fifty-five trillion, two hundred twenty-one billion, twelve million, ten thousand, seven hundred twenty-one".