55136215621 has 2 divisors, whose sum is σ = 55136215622. Its totient is φ = 55136215620.

The previous prime is 55136215613. The next prime is 55136215661. The reversal of 55136215621 is 12651263155.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44504543521 + 10631672100 = 210961^2 + 103110^2 .

It is a cyclic number.

It is not a de Polignac number, because 55136215621 - 2³ = 55136215613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55136215661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27568107810 + 27568107811.

It is an arithmetic number, because the mean of its divisors is an integer number (27568107811).

Almost surely, 2^55136215621 is an apocalyptic number.

It is an amenable number.

55136215621 is a deficient number, since it is larger than the sum of its proper divisors (1).

55136215621 is an equidigital number, since it uses as much as digits as its factorization.

55136215621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54000, while the sum is 37.

Adding to 55136215621 its reverse (12651263155), we get a palindrome (67787478776).

The spelling of 55136215621 in words is "fifty-five billion, one hundred thirty-six million, two hundred fifteen thousand, six hundred twenty-one".