521212440 has 64 divisors (see below), whose sum is σ = 1787016960. Its totient is φ = 119134080.

The previous prime is 521212429. The next prime is 521212463. The reversal of 521212440 is 44212125.

It is a super-2 number, since 2×521212440² = 543324815221507200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 309406 + ... + 311085.

It is an arithmetic number, because the mean of its divisors is an integer number (27922140).

Almost surely, 2^521212440 is an apocalyptic number.

It is an amenable number.

521212440 is an abundant number, since it is smaller than the sum of its proper divisors (1265804520).

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

521212440 is a wasteful number, since it uses less digits than its factorization.

521212440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 620512 (or 620508 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 21.

The square root of 521212440 is about 22830.0775294347. The cubic root of 521212440 is about 804.7696523397.

Adding to 521212440 its reverse (44212125), we get a palindrome (565424565).

The spelling of 521212440 in words is "five hundred twenty-one million, two hundred twelve thousand, four hundred forty".