55278813661 has 2 divisors, whose sum is σ = 55278813662. Its totient is φ = 55278813660.

The previous prime is 55278813619. The next prime is 55278813671. The reversal of 55278813661 is 16631887255.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43911202500 + 11367611161 = 209550^2 + 106619^2 .

It is a cyclic number.

It is not a de Polignac number, because 55278813661 - 2¹³ = 55278805469 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 55278813599 and 55278813608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55278813671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27639406830 + 27639406831.

It is an arithmetic number, because the mean of its divisors is an integer number (27639406831).

Almost surely, 2^55278813661 is an apocalyptic number.

It is an amenable number.

55278813661 is a deficient number, since it is larger than the sum of its proper divisors (1).

55278813661 is an equidigital number, since it uses as much as digits as its factorization.

55278813661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2419200, while the sum is 52.

It can be divided in two parts, 5527 and 8813661, that added together give a palindrome (8819188).

The spelling of 55278813661 in words is "fifty-five billion, two hundred seventy-eight million, eight hundred thirteen thousand, six hundred sixty-one".