521661338 has 16 divisors (see below), whose sum is σ = 883064160. Its totient is φ = 228942000.

The previous prime is 521661331. The next prime is 521661341. The reversal of 521661338 is 833166125.

It is a junction number, because it is equal to n+sod(n) for n = 521661298 and 521661307.

It is not an unprimeable number, because it can be changed into a prime (521661331) 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, 408188 + ... + 409463.

It is an arithmetic number, because the mean of its divisors is an integer number (55191510).

Almost surely, 2^521661338 is an apocalyptic number.

521661338 is a gapful number since it is divisible by the number (58) formed by its first and last digit.

521661338 is a deficient number, since it is larger than the sum of its proper divisors (361402822).

521661338 is a wasteful number, since it uses less digits than its factorization.

521661338 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 817693.

The product of its digits is 25920, while the sum is 35.

The square root of 521661338 is about 22839.9066985835. The cubic root of 521661338 is about 805.0006239466. Note that the first 3 decimals are identical.

The spelling of 521661338 in words is "five hundred twenty-one million, six hundred sixty-one thousand, three hundred thirty-eight".