551381 has 2 divisors, whose sum is σ = 551382. Its totient is φ = 551380.

The previous prime is 551363. The next prime is 551387. The reversal of 551381 is 183155.

551381 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., 422500 + 128881 = 650^2 + 359^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-551381 is a prime.

It is a super-2 number, since 2×551381² = 608042014322, which contains 22 as substring.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 551381.

It is not a weakly prime, because it can be changed into another prime (551387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 275690 + 275691.

It is an arithmetic number, because the mean of its divisors is an integer number (275691).

2⁵⁵¹³⁸¹ is an apocalyptic number.

It is an amenable number.

551381 is a deficient number, since it is larger than the sum of its proper divisors (1).

551381 is an equidigital number, since it uses as much as digits as its factorization.

551381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 600, while the sum is 23.

The square root of 551381 is about 742.5503349942. The cubic root of 551381 is about 82.0006444526. Note that the first 3 decimals are identical.

The spelling of 551381 in words is "five hundred fifty-one thousand, three hundred eighty-one".