816090421 has 12 divisors (see below), whose sum is σ = 864896032. Its totient is φ = 769590864.

The previous prime is 816090383. The next prime is 816090437. The reversal of 816090421 is 124090618.

It is a happy number.

It is not a de Polignac number, because 816090421 - 2¹⁹ = 815566133 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816090721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24880 + ... + 47446.

Almost surely, 2^816090421 is an apocalyptic number.

It is an amenable number.

816090421 is a deficient number, since it is larger than the sum of its proper divisors (48805611).

816090421 is a wasteful number, since it uses less digits than its factorization.

816090421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22668 (or 22639 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 816090421 is about 28567.2963543980. The cubic root of 816090421 is about 934.5002604612.

The spelling of 816090421 in words is "eight hundred sixteen million, ninety thousand, four hundred twenty-one".