55151721555 has 64 divisors (see below), whose sum is σ = 108244159488. Its totient is φ = 23404032000.

The previous prime is 55151721533. The next prime is 55151721557. The reversal of 55151721555 is 55512715155.

It is not a de Polignac number, because 55151721555 - 2⁹ = 55151721043 is a prime.

It is not an unprimeable number, because it can be changed into a prime (55151721557) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 81321 + ... + 341930.

It is an arithmetic number, because the mean of its divisors is an integer number (1691314992).

Almost surely, 2^55151721555 is an apocalyptic number.

55151721555 is a deficient number, since it is larger than the sum of its proper divisors (53092437933).

55151721555 is a wasteful number, since it uses less digits than its factorization.

55151721555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 423356.

The product of its digits is 218750, while the sum is 42.

The spelling of 55151721555 in words is "fifty-five billion, one hundred fifty-one million, seven hundred twenty-one thousand, five hundred fifty-five".