55511555021 has 4 divisors (see below), whose sum is σ = 59781674652. Its totient is φ = 51241435392.

The previous prime is 55511555017. The next prime is 55511555023. The reversal of 55511555021 is 12055511555.

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 3795792100 + 51715762921 = 61610^2 + 227411^2 .

It is a cyclic number.

It is not a de Polignac number, because 55511555021 - 2² = 55511555017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55511555023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2135059796 + ... + 2135059821.

It is an arithmetic number, because the mean of its divisors is an integer number (14945418663).

Almost surely, 2^55511555021 is an apocalyptic number.

It is an amenable number.

55511555021 is a deficient number, since it is larger than the sum of its proper divisors (4270119631).

55511555021 is a wasteful number, since it uses less digits than its factorization.

55511555021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4270119630.

The product of its (nonzero) digits is 31250, while the sum is 35.

The spelling of 55511555021 in words is "fifty-five billion, five hundred eleven million, five hundred fifty-five thousand, twenty-one".