1056721556 has 72 divisors (see below), whose sum is σ = 2156642880. Its totient is φ = 451440000.

The previous prime is 1056721553. The next prime is 1056721597. The reversal of 1056721556 is 6551276501.

It is a super-2 number, since 2×1056721556² = 2233320893830122272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1056721553) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 1388216 + ... + 1388976.

Almost surely, 2^1056721556 is an apocalyptic number.

It is an amenable number.

1056721556 is an abundant number, since it is smaller than the sum of its proper divisors (1099921324).

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

1056721556 is a wasteful number, since it uses less digits than its factorization.

1056721556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 957 (or 944 counting only the distinct ones).

The product of its (nonzero) digits is 63000, while the sum is 38.

The square root of 1056721556 is about 32507.2538981686. The cubic root of 1056721556 is about 1018.5605596237.

Subtracting 1056721556 from its reverse (6551276501), we obtain a palindrome (5494554945).

It can be divided in two parts, 10567 and 21556, that added together give a palindrome (32123).

The spelling of 1056721556 in words is "one billion, fifty-six million, seven hundred twenty-one thousand, five hundred fifty-six".