521690 has 16 divisors (see below), whose sum is σ = 1011528. Its totient is φ = 192576.

The previous prime is 521671. The next prime is 521693. The reversal of 521690 is 96125.

It can be written as a sum of positive squares in 4 ways, for example, as 413449 + 108241 = 643^2 + 329^2 .

It is a super-2 number, since 2×521690² = 544320912200, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (521693) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1877 + ... + 2136.

2⁵²¹⁶⁹⁰ is an apocalyptic number.

521690 is a deficient number, since it is larger than the sum of its proper divisors (489838).

521690 is a wasteful number, since it uses less digits than its factorization.

521690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4033.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 521690 is about 722.2811087105. The cubic root of 521690 is about 80.5015366912.

The spelling of 521690 in words is "five hundred twenty-one thousand, six hundred ninety".