16556510421 has 24 divisors (see below), whose sum is σ = 26114512320. Its totient is φ = 10024454400.

The previous prime is 16556510389. The next prime is 16556510429. The reversal of 16556510421 is 12401565561.

16556510421 is a `hidden beast` number, since 1 + 65 + 565 + 10 + 4 + 21 = 666.

It is not a de Polignac number, because 16556510421 - 2⁵ = 16556510389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16556510429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20965 + ... + 183173.

It is an arithmetic number, because the mean of its divisors is an integer number (1088104680).

Almost surely, 2^16556510421 is an apocalyptic number.

16556510421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16556510421 is a deficient number, since it is larger than the sum of its proper divisors (9558001899).

16556510421 is a wasteful number, since it uses less digits than its factorization.

16556510421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163257 (or 163254 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

The spelling of 16556510421 in words is "sixteen billion, five hundred fifty-six million, five hundred ten thousand, four hundred twenty-one".