521200121 has 4 divisors (see below), whose sum is σ = 561292452. Its totient is φ = 481107792.

The previous prime is 521200087. The next prime is 521200129. The reversal of 521200121 is 121002125.

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

It can be written as a sum of positive squares in 2 ways, for example, as 60668521 + 460531600 = 7789^2 + 21460^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-521200121 is a prime.

It is a super-2 number, since 2×521200121² = 543299132260829282, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 521200096 and 521200105.

It is not an unprimeable number, because it can be changed into a prime (521200129) 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, 20046146 + ... + 20046171.

It is an arithmetic number, because the mean of its divisors is an integer number (140323113).

Almost surely, 2^521200121 is an apocalyptic number.

It is an amenable number.

521200121 is a deficient number, since it is larger than the sum of its proper divisors (40092331).

521200121 is a wasteful number, since it uses less digits than its factorization.

521200121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40092330.

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 521200121 is about 22829.8077302460. The cubic root of 521200121 is about 804.7633119720.

Adding to 521200121 its reverse (121002125), we get a palindrome (642202246).

The spelling of 521200121 in words is "five hundred twenty-one million, two hundred thousand, one hundred twenty-one".