521357985 has 16 divisors (see below), whose sum is σ = 926858880. Its totient is φ = 278057520.

The previous prime is 521357983. The next prime is 521357999. The reversal of 521357985 is 589753125.

521357985 is a `hidden beast` number, since 521 + 35 + 7 + 98 + 5 = 666.

It is not a de Polignac number, because 521357985 - 2¹ = 521357983 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 521357985.

It is not an unprimeable number, because it can be changed into a prime (521357983) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1930821 + ... + 1931090.

It is an arithmetic number, because the mean of its divisors is an integer number (57928680).

Almost surely, 2^521357985 is an apocalyptic number.

It is an amenable number.

521357985 is a deficient number, since it is larger than the sum of its proper divisors (405500895).

521357985 is a wasteful number, since it uses less digits than its factorization.

521357985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3861925 (or 3861919 counting only the distinct ones).

The product of its digits is 378000, while the sum is 45.

The square root of 521357985 is about 22833.2648782429. The cubic root of 521357985 is about 804.8445541706.

The spelling of 521357985 in words is "five hundred twenty-one million, three hundred fifty-seven thousand, nine hundred eighty-five".