521397 has 20 divisors (see below), whose sum is σ = 802956. Its totient is φ = 336960.

The previous prime is 521393. The next prime is 521399. The reversal of 521397 is 793125.

It can be written as a sum of positive squares in 2 ways, for example, as 77841 + 443556 = 279^2 + 666^2 .

It is not a de Polignac number, because 521397 - 2² = 521393 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

Its product of digits (1890) is a multiple of the sum of its prime factors (210).

It is a nialpdrome in base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 521397.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3243 + ... + 3399.

2⁵²¹³⁹⁷ is an apocalyptic number.

It is an amenable number.

521397 is a deficient number, since it is larger than the sum of its proper divisors (281559).

521397 is a wasteful number, since it uses less digits than its factorization.

521397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210 (or 201 counting only the distinct ones).

The product of its digits is 1890, while the sum is 27.

The square root of 521397 is about 722.0782506072. The cubic root of 521397 is about 80.4864630093.

The spelling of 521397 in words is "five hundred twenty-one thousand, three hundred ninety-seven".