55775821 has 2 divisors, whose sum is σ = 55775822. Its totient is φ = 55775820.

The previous prime is 55775813. The next prime is 55775831. The reversal of 55775821 is 12857755.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47073321 + 8702500 = 6861^2 + 2950^2 .

It is a cyclic number.

It is not a de Polignac number, because 55775821 - 2³ = 55775813 is a prime.

It is a super-2 number, since 2×55775821² = 6221884416448082, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55775831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27887910 + 27887911.

It is an arithmetic number, because the mean of its divisors is an integer number (27887911).

Almost surely, 2^55775821 is an apocalyptic number.

It is an amenable number.

55775821 is a deficient number, since it is larger than the sum of its proper divisors (1).

55775821 is an equidigital number, since it uses as much as digits as its factorization.

55775821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 98000, while the sum is 40.

The square root of 55775821 is about 7468.3211634209. The cubic root of 55775821 is about 382.0750311760.

The spelling of 55775821 in words is "fifty-five million, seven hundred seventy-five thousand, eight hundred twenty-one".