521860921 has 8 divisors (see below), whose sum is σ = 524096384. Its totient is φ = 519631200.

The previous prime is 521860909. The next prime is 521860957. The reversal of 521860921 is 129068125.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 521860921 - 2⁷ = 521860793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521863921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 291796 + ... + 293578.

It is an arithmetic number, because the mean of its divisors is an integer number (65512048).

Almost surely, 2^521860921 is an apocalyptic number.

It is an amenable number.

521860921 is a deficient number, since it is larger than the sum of its proper divisors (2235463).

521860921 is a wasteful number, since it uses less digits than its factorization.

521860921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2871.

The product of its (nonzero) digits is 8640, while the sum is 34.

The square root of 521860921 is about 22844.2754536011. The cubic root of 521860921 is about 805.1032728893.

The spelling of 521860921 in words is "five hundred twenty-one million, eight hundred sixty thousand, nine hundred twenty-one".