55520531021 has 2 divisors, whose sum is σ = 55520531022. Its totient is φ = 55520531020.

The previous prime is 55520530997. The next prime is 55520531023. The reversal of 55520531021 is 12013502555.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31367952100 + 24152578921 = 177110^2 + 155411^2 .

It is a cyclic number.

It is not a de Polignac number, because 55520531021 - 2¹⁰ = 55520529997 is a prime.

Together with 55520531023, 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 (55520531023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27760265510 + 27760265511.

It is an arithmetic number, because the mean of its divisors is an integer number (27760265511).

Almost surely, 2^55520531021 is an apocalyptic number.

It is an amenable number.

55520531021 is a deficient number, since it is larger than the sum of its proper divisors (1).

55520531021 is an equidigital number, since it uses as much as digits as its factorization.

55520531021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7500, while the sum is 29.

The spelling of 55520531021 in words is "fifty-five billion, five hundred twenty million, five hundred thirty-one thousand, twenty-one".