5638555421 has 2 divisors, whose sum is σ = 5638555422. Its totient is φ = 5638555420.

The previous prime is 5638555369. The next prime is 5638555423. The reversal of 5638555421 is 1245558365.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5637907396 + 648025 = 75086^2 + 805^2 .

It is a cyclic number.

It is not a de Polignac number, because 5638555421 - 2⁶ = 5638555357 is a prime.

Together with 5638555423, 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 (5638555423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2819277710 + 2819277711.

It is an arithmetic number, because the mean of its divisors is an integer number (2819277711).

Almost surely, 2^5638555421 is an apocalyptic number.

It is an amenable number.

5638555421 is a deficient number, since it is larger than the sum of its proper divisors (1).

5638555421 is an equidigital number, since it uses as much as digits as its factorization.

5638555421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720000, while the sum is 44.

The square root of 5638555421 is about 75090.3150945580. The cubic root of 5638555421 is about 1779.8741043181.

The spelling of 5638555421 in words is "five billion, six hundred thirty-eight million, five hundred fifty-five thousand, four hundred twenty-one".