66521199 has 8 divisors (see below), whose sum is σ = 89290800. Its totient is φ = 44049536.

The previous prime is 66521159. The next prime is 66521207. The reversal of 66521199 is 99112566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66521199 - 2¹⁵ = 66488431 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66521149) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 73962 + ... + 74855.

It is an arithmetic number, because the mean of its divisors is an integer number (11161350).

Almost surely, 2^66521199 is an apocalyptic number.

66521199 is a deficient number, since it is larger than the sum of its proper divisors (22769601).

66521199 is a wasteful number, since it uses less digits than its factorization.

66521199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148969.

The product of its digits is 29160, while the sum is 39.

The square root of 66521199 is about 8156.0529056646. The cubic root of 66521199 is about 405.1849970261.

It can be divided in two parts, 6652119 and 9, that added together give a triangular number (6652128 = T₃₆₄₇).

The spelling of 66521199 in words is "sixty-six million, five hundred twenty-one thousand, one hundred ninety-nine".