521951987 has 4 divisors (see below), whose sum is σ = 525077616. Its totient is φ = 518826360.

The previous prime is 521951977. The next prime is 521951999. The reversal of 521951987 is 789159125.

It is a happy number.

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 521951987 - 2⁶ = 521951923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521951957) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1562564 + ... + 1562897.

It is an arithmetic number, because the mean of its divisors is an integer number (131269404).

Almost surely, 2^521951987 is an apocalyptic number.

521951987 is a deficient number, since it is larger than the sum of its proper divisors (3125629).

521951987 is a wasteful number, since it uses less digits than its factorization.

521951987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3125628.

The product of its digits is 226800, while the sum is 47.

The square root of 521951987 is about 22846.2685574691. The cubic root of 521951987 is about 805.1501009919.

The spelling of 521951987 in words is "five hundred twenty-one million, nine hundred fifty-one thousand, nine hundred eighty-seven".