66858540 has 72 divisors (see below), whose sum is σ = 217777392. Its totient is φ = 15281280.

The previous prime is 66858527. The next prime is 66858541. The reversal of 66858540 is 4585866.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 66858492 and 66858501.

It is not an unprimeable number, because it can be changed into a prime (66858541) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8431 + ... + 14310.

It is an arithmetic number, because the mean of its divisors is an integer number (3024686).

Almost surely, 2^66858540 is an apocalyptic number.

66858540 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66858540 is an abundant number, since it is smaller than the sum of its proper divisors (150918852).

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

66858540 is a wasteful number, since it uses less digits than its factorization.

66858540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22767 (or 22758 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 42.

The square root of 66858540 is about 8176.7071611988. The cubic root of 66858540 is about 405.8687645598.

It can be divided in two parts, 6685 and 8540, that added together give a triangular number (15225 = T₁₇₄).

The spelling of 66858540 in words is "sixty-six million, eight hundred fifty-eight thousand, five hundred forty".