550991681 has 2 divisors, whose sum is σ = 550991682. Its totient is φ = 550991680.

The previous prime is 550991603. The next prime is 550991687. The reversal of 550991681 is 186199055.

550991681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 490401025 + 60590656 = 22145^2 + 7784^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-550991681 is a prime.

It is a super-2 number, since 2×550991681² = 607183665062411522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (550991687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 275495840 + 275495841.

It is an arithmetic number, because the mean of its divisors is an integer number (275495841).

Almost surely, 2^550991681 is an apocalyptic number.

It is an amenable number.

550991681 is a deficient number, since it is larger than the sum of its proper divisors (1).

550991681 is an equidigital number, since it uses as much as digits as its factorization.

550991681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 97200, while the sum is 44.

The square root of 550991681 is about 23473.2119872846. The cubic root of 550991681 is about 819.8134024155.

The spelling of 550991681 in words is "five hundred fifty million, nine hundred ninety-one thousand, six hundred eighty-one".