66011556 has 48 divisors (see below), whose sum is σ = 166471424. Its totient is φ = 20238336.

The previous prime is 66011509. The next prime is 66011557. The reversal of 66011556 is 65511066.

It is a super-2 number, since 2×66011556² = 8715051051082272, which contains 22 as substring.

It is a zygodrome in base 5.

It is not an unprimeable number, because it can be changed into a prime (66011557) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56676 + ... + 57828.

Almost surely, 2^66011556 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 66011556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83235712).

66011556 is an abundant number, since it is smaller than the sum of its proper divisors (100459868).

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

66011556 is a wasteful number, since it uses less digits than its factorization.

66011556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1540 (or 1538 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 66011556 is about 8124.7495961414. The cubic root of 66011556 is about 404.1475868321.

It can be divided in two parts, 6601155 and 6, that added together give a triangular number (6601161 = T₃₆₃₃).

The spelling of 66011556 in words is "sixty-six million, eleven thousand, five hundred fifty-six".