16556211225 has 18 divisors (see below), whose sum is σ = 29654014286. Its totient is φ = 8829979200.

The previous prime is 16556211223. The next prime is 16556211263. The reversal of 16556211225 is 52211265561.

16556211225 is a `hidden beast` number, since 1 + 6 + 5 + 5 + 621 + 1 + 2 + 25 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 382476249 + 16173734976 = 19557^2 + 127176^2 .

It is not a de Polignac number, because 16556211225 - 2¹ = 16556211223 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 16556211225.

It is not an unprimeable number, because it can be changed into a prime (16556211223) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 36791356 + ... + 36791805.

Almost surely, 2^16556211225 is an apocalyptic number.

16556211225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16556211225 is a deficient number, since it is larger than the sum of its proper divisors (13097803061).

16556211225 is a wasteful number, since it uses less digits than its factorization.

16556211225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73583177 (or 73583169 counting only the distinct ones).

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

Adding to 16556211225 its reverse (52211265561), we get a palindrome (68767476786).

The spelling of 16556211225 in words is "sixteen billion, five hundred fifty-six million, two hundred eleven thousand, two hundred twenty-five".