11506721556 has 48 divisors (see below), whose sum is σ = 30831413760. Its totient is φ = 3303364320.

The previous prime is 11506721521. The next prime is 11506721581. The reversal of 11506721556 is 65512760511.

It is a happy number.

11506721556 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×11506721556² (a number of 21 digits) 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 15 ways as a sum of consecutive naturals, for example, 2291496 + ... + 2296511.

It is an arithmetic number, because the mean of its divisors is an integer number (642321120).

Almost surely, 2^11506721556 is an apocalyptic number.

It is an amenable number.

11506721556 is an abundant number, since it is smaller than the sum of its proper divisors (19324692204).

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

11506721556 is a wasteful number, since it uses less digits than its factorization.

11506721556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4588044 (or 4588042 counting only the distinct ones).

The product of its (nonzero) digits is 63000, while the sum is 39.

The spelling of 11506721556 in words is "eleven billion, five hundred six million, seven hundred twenty-one thousand, five hundred fifty-six".