521050021 has 4 divisors (see below), whose sum is σ = 535132492. Its totient is φ = 506967552.

The previous prime is 521050007. The next prime is 521050039. The reversal of 521050021 is 120050125.

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 228161025 + 292888996 = 15105^2 + 17114^2 .

It is a cyclic number.

It is not a de Polignac number, because 521050021 - 2¹⁵ = 521017253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 521049977 and 521050004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521050081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7041180 + ... + 7041253.

It is an arithmetic number, because the mean of its divisors is an integer number (133783123).

Almost surely, 2^521050021 is an apocalyptic number.

It is an amenable number.

521050021 is a deficient number, since it is larger than the sum of its proper divisors (14082471).

521050021 is a wasteful number, since it uses less digits than its factorization.

521050021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14082470.

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 521050021 is about 22826.5201246270. The cubic root of 521050021 is about 804.6860501769.

The spelling of 521050021 in words is "five hundred twenty-one million, fifty thousand, twenty-one".