66820572 has 144 divisors (see below), whose sum is σ = 214798080. Its totient is φ = 17589312.

The previous prime is 66820571. The next prime is 66820583. The reversal of 66820572 is 27502866.

66820572 is a `hidden beast` number, since 6 + 6 + 82 + 0 + 572 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66820571) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 127503 + ... + 128025.

Almost surely, 2^66820572 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 66820572, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107399040).

66820572 is an abundant number, since it is smaller than the sum of its proper divisors (147977508).

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

66820572 is a wasteful number, since it uses less digits than its factorization.

66820572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 569 (or 548 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 66820572 is about 8174.3851144903. The cubic root of 66820572 is about 405.7919210072.

The spelling of 66820572 in words is "sixty-six million, eight hundred twenty thousand, five hundred seventy-two".