20051556 has 24 divisors (see below), whose sum is σ = 53471040. Its totient is φ = 5728992.

The previous prime is 20051539. The next prime is 20051587. The reversal of 20051556 is 65515002.

It is a super-2 number, since 2×20051556² = 804129796042272, which contains 22 as substring.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 119271 + ... + 119438.

It is an arithmetic number, because the mean of its divisors is an integer number (2227960).

Almost surely, 2^20051556 is an apocalyptic number.

It is an amenable number.

20051556 is an abundant number, since it is smaller than the sum of its proper divisors (33419484).

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

20051556 is a wasteful number, since it uses less digits than its factorization.

20051556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238723 (or 238721 counting only the distinct ones).

The product of its (nonzero) digits is 1500, while the sum is 24.

The square root of 20051556 is about 4477.8963811147. The cubic root of 20051556 is about 271.6748023877.

Adding to 20051556 its reverse (65515002), we get a palindrome (85566558).

The spelling of 20051556 in words is "twenty million, fifty-one thousand, five hundred fifty-six".