66456021 has 4 divisors (see below), whose sum is σ = 88608032. Its totient is φ = 44304012.

The previous prime is 66456017. The next prime is 66456067. The reversal of 66456021 is 12065466.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 66456021 - 2² = 66456017 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66456021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66456001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11076001 + ... + 11076006.

It is an arithmetic number, because the mean of its divisors is an integer number (22152008).

Almost surely, 2^66456021 is an apocalyptic number.

It is an amenable number.

66456021 is a deficient number, since it is larger than the sum of its proper divisors (22152011).

66456021 is a wasteful number, since it uses less digits than its factorization.

66456021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22152010.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 66456021 is about 8152.0562436725. The cubic root of 66456021 is about 405.0526192873.

The spelling of 66456021 in words is "sixty-six million, four hundred fifty-six thousand, twenty-one".