55090781 has 2 divisors, whose sum is σ = 55090782. Its totient is φ = 55090780.

The previous prime is 55090771. The next prime is 55090793. The reversal of 55090781 is 18709055.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53158681 + 1932100 = 7291^2 + 1390^2 .

It is a cyclic number.

It is not a de Polignac number, because 55090781 - 2¹⁰ = 55089757 is a prime.

It is a super-2 number, since 2×55090781² = 6069988302379922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55090741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27545390 + 27545391.

It is an arithmetic number, because the mean of its divisors is an integer number (27545391).

Almost surely, 2^55090781 is an apocalyptic number.

It is an amenable number.

55090781 is a deficient number, since it is larger than the sum of its proper divisors (1).

55090781 is an equidigital number, since it uses as much as digits as its factorization.

55090781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12600, while the sum is 35.

The square root of 55090781 is about 7422.3164173996. The cubic root of 55090781 is about 380.5043648984.

The spelling of 55090781 in words is "fifty-five million, ninety thousand, seven hundred eighty-one".