521443987 has 2 divisors, whose sum is σ = 521443988. Its totient is φ = 521443986.

The previous prime is 521443939. The next prime is 521444039. The reversal of 521443987 is 789344125.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 521443987 - 2⁷ = 521443859 is a prime.

It is not a weakly prime, because it can be changed into another prime (521443927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260721993 + 260721994.

It is an arithmetic number, because the mean of its divisors is an integer number (260721994).

Almost surely, 2^521443987 is an apocalyptic number.

521443987 is a deficient number, since it is larger than the sum of its proper divisors (1).

521443987 is an equidigital number, since it uses as much as digits as its factorization.

521443987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 241920, while the sum is 43.

The square root of 521443987 is about 22835.1480617052. The cubic root of 521443987 is about 804.8888068323. Note that the first 4 decimals are identical.

The spelling of 521443987 in words is "five hundred twenty-one million, four hundred forty-three thousand, nine hundred eighty-seven".