55028660021 has 2 divisors, whose sum is σ = 55028660022. Its totient is φ = 55028660020.

The previous prime is 55028659963. The next prime is 55028660023. The reversal of 55028660021 is 12006682055.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 33046149796 + 21982510225 = 181786^2 + 148265^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55028660021 is a prime.

Together with 55028660023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55028660023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27514330010 + 27514330011.

It is an arithmetic number, because the mean of its divisors is an integer number (27514330011).

Almost surely, 2^55028660021 is an apocalyptic number.

It is an amenable number.

55028660021 is a deficient number, since it is larger than the sum of its proper divisors (1).

55028660021 is an equidigital number, since it uses as much as digits as its factorization.

55028660021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28800, while the sum is 35.

The spelling of 55028660021 in words is "fifty-five billion, twenty-eight million, six hundred sixty thousand, twenty-one".