521378861 has 8 divisors (see below), whose sum is σ = 531878400. Its totient is φ = 510903952.

The previous prime is 521378839. The next prime is 521378873. The reversal of 521378861 is 168873125.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-521378861 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 (521378161) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40040 + ... + 51438.

It is an arithmetic number, because the mean of its divisors is an integer number (66484800).

Almost surely, 2^521378861 is an apocalyptic number.

It is an amenable number.

521378861 is a deficient number, since it is larger than the sum of its proper divisors (10499539).

521378861 is a wasteful number, since it uses less digits than its factorization.

521378861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12315.

The product of its digits is 80640, while the sum is 41.

The square root of 521378861 is about 22833.7220137235. The cubic root of 521378861 is about 804.8552964444.

The spelling of 521378861 in words is "five hundred twenty-one million, three hundred seventy-eight thousand, eight hundred sixty-one".