521682421 has 16 divisors (see below), whose sum is σ = 583173360. Its totient is φ = 463357440.

The previous prime is 521682419. The next prime is 521682439. The reversal of 521682421 is 124286125.

It can be written as a sum of positive squares in 8 ways, for example, as 63123025 + 458559396 = 7945^2 + 21414^2 .

It is not a de Polignac number, because 521682421 - 2¹ = 521682419 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521682521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 115791 + ... + 120211.

It is an arithmetic number, because the mean of its divisors is an integer number (36448335).

Almost surely, 2^521682421 is an apocalyptic number.

It is an amenable number.

521682421 is a deficient number, since it is larger than the sum of its proper divisors (61490939).

521682421 is a wasteful number, since it uses less digits than its factorization.

521682421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4776.

The product of its digits is 7680, while the sum is 31.

The square root of 521682421 is about 22840.3682325833. The cubic root of 521682421 is about 805.0114685299.

The spelling of 521682421 in words is "five hundred twenty-one million, six hundred eighty-two thousand, four hundred twenty-one".