521640370 has 16 divisors (see below), whose sum is σ = 939912408. Its totient is φ = 208442880.

The previous prime is 521640349. The next prime is 521640377. The reversal of 521640370 is 73046125.

It can be written as a sum of positive squares in 4 ways, for example, as 451265049 + 70375321 = 21243^2 + 8389^2 .

It is a super-2 number, since 2×521640370² = 544217351227473800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (521640377) 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 7 ways as a sum of consecutive naturals, for example, 16191 + ... + 36130.

Almost surely, 2^521640370 is an apocalyptic number.

521640370 is a deficient number, since it is larger than the sum of its proper divisors (418272038).

521640370 is a wasteful number, since it uses less digits than its factorization.

521640370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53325.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 521640370 is about 22839.4476728313. The cubic root of 521640370 is about 804.9898382267.

Adding to 521640370 its reverse (73046125), we get a palindrome (594686495).

The spelling of 521640370 in words is "five hundred twenty-one million, six hundred forty thousand, three hundred seventy".