551391 has 4 divisors (see below), whose sum is σ = 735192. Its totient is φ = 367592.

The previous prime is 551387. The next prime is 551407. The reversal of 551391 is 193155.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 551391 - 2² = 551387 is a prime.

It is a D-number.

551391 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (551311) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 91896 + ... + 91901.

It is an arithmetic number, because the mean of its divisors is an integer number (183798).

2⁵⁵¹³⁹¹ is an apocalyptic number.

551391 is a deficient number, since it is larger than the sum of its proper divisors (183801).

551391 is a wasteful number, since it uses less digits than its factorization.

551391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183800.

The product of its digits is 675, while the sum is 24.

The square root of 551391 is about 742.5570685139. The cubic root of 551391 is about 82.0011401785.

The spelling of 551391 in words is "five hundred fifty-one thousand, three hundred ninety-one".