819914521 has 4 divisors (see below), whose sum is σ = 820035792. Its totient is φ = 819793252.

The previous prime is 819914509. The next prime is 819914533. The reversal of 819914521 is 125419918.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (819914509) and next prime (819914533).

It is a cyclic number.

It is not a de Polignac number, because 819914521 - 2⁵ = 819914489 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (819914551) 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, 49855 + ... + 64228.

It is an arithmetic number, because the mean of its divisors is an integer number (205008948).

Almost surely, 2^819914521 is an apocalyptic number.

It is an amenable number.

819914521 is a deficient number, since it is larger than the sum of its proper divisors (121271).

819914521 is a wasteful number, since it uses less digits than its factorization.

819914521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121270.

The product of its digits is 25920, while the sum is 40.

The square root of 819914521 is about 28634.1495595731. The cubic root of 819914521 is about 935.9576378087.

The spelling of 819914521 in words is "eight hundred nineteen million, nine hundred fourteen thousand, five hundred twenty-one".