521840340 has 96 divisors (see below), whose sum is σ = 1855445760. Its totient is φ = 119276928.

The previous prime is 521840327. The next prime is 521840387. The reversal of 521840340 is 43048125.

521840340 is a `hidden beast` number, since 5 + 218 + 403 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 65247 + ... + 72806.

It is an arithmetic number, because the mean of its divisors is an integer number (19327560).

Almost surely, 2^521840340 is an apocalyptic number.

It is an amenable number.

521840340 is an abundant number, since it is smaller than the sum of its proper divisors (1333605420).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

521840340 is a wasteful number, since it uses less digits than its factorization.

521840340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138078 (or 138070 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 521840340 is about 22843.8249861970. The cubic root of 521840340 is about 805.0926889402.

Adding to 521840340 its reverse (43048125), we get a palindrome (564888465).

The spelling of 521840340 in words is "five hundred twenty-one million, eight hundred forty thousand, three hundred forty".