521979999 has 4 divisors (see below), whose sum is σ = 695973336. Its totient is φ = 347986664.

The previous prime is 521979977. The next prime is 521980037. The reversal of 521979999 is 999979125.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 521979999 - 2⁸ = 521979743 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521979949) 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 3 ways as a sum of consecutive naturals, for example, 86996664 + ... + 86996669.

It is an arithmetic number, because the mean of its divisors is an integer number (173993334).

Almost surely, 2^521979999 is an apocalyptic number.

521979999 is a deficient number, since it is larger than the sum of its proper divisors (173993337).

521979999 is a wasteful number, since it uses less digits than its factorization.

521979999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173993336.

The product of its digits is 4133430, while the sum is 60.

The square root of 521979999 is about 22846.8816034049. The cubic root of 521979999 is about 805.1645042715.

The spelling of 521979999 in words is "five hundred twenty-one million, nine hundred seventy-nine thousand, nine hundred ninety-nine".