16121556 has 54 divisors (see below), whose sum is σ = 44805306. Its totient is φ = 4884000.

The previous prime is 16121537. The next prime is 16121561. The reversal of 16121556 is 65512161.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 13176900 + 2944656 = 3630^2 + 1716^2 .

It is a super-2 number, since 2×16121556² = 519809135722272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 17 ways as a sum of consecutive naturals, for example, 2506 + ... + 6206.

Almost surely, 2^16121556 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16121556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22402653).

16121556 is an abundant number, since it is smaller than the sum of its proper divisors (28683750).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

16121556 is a wasteful number, since it uses less digits than its factorization.

16121556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3733 (or 3717 counting only the distinct ones).

The product of its digits is 1800, while the sum is 27.

The square root of 16121556 is about 4015.1657500034. The cubic root of 16121556 is about 252.6207297698.

It can be divided in two parts, 1612155 and 6, that added together give a palindrome (1612161).

The spelling of 16121556 in words is "sixteen million, one hundred twenty-one thousand, five hundred fifty-six".