66216501 has 32 divisors (see below), whose sum is σ = 111216000. Its totient is φ = 38600064.

The previous prime is 66216499. The next prime is 66216511. The reversal of 66216501 is 10561266.

It is a happy number.

66216501 is a `hidden beast` number, since 6 + 6 + 2 + 1 + 650 + 1 = 666.

It is not a de Polignac number, because 66216501 - 2¹ = 66216499 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66216511) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1705 + ... + 11633.

It is an arithmetic number, because the mean of its divisors is an integer number (3475500).

Almost surely, 2^66216501 is an apocalyptic number.

It is an amenable number.

66216501 is a deficient number, since it is larger than the sum of its proper divisors (44999499).

66216501 is a wasteful number, since it uses less digits than its factorization.

66216501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9970 (or 9964 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 66216501 is about 8137.3522106395. The cubic root of 66216501 is about 404.5654048701.

Adding to 66216501 its reverse (10561266), we get a palindrome (76777767).

The spelling of 66216501 in words is "sixty-six million, two hundred sixteen thousand, five hundred one".