66464021 has 8 divisors (see below), whose sum is σ = 71652504. Its totient is φ = 61286400.

The previous prime is 66464003. The next prime is 66464039. The reversal of 66464021 is 12046466.

It is an interprime number because it is at equal distance from previous prime (66464003) and next prime (66464039).

It can be written as a sum of positive squares in 4 ways, for example, as 1661521 + 64802500 = 1289^2 + 8050^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66464021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66464051) 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, 13721 + ... + 17921.

It is an arithmetic number, because the mean of its divisors is an integer number (8956563).

Almost surely, 2^66464021 is an apocalyptic number.

It is an amenable number.

66464021 is a deficient number, since it is larger than the sum of its proper divisors (5188483).

66464021 is a wasteful number, since it uses less digits than its factorization.

66464021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5431.

The product of its (nonzero) digits is 6912, while the sum is 29.

The square root of 66464021 is about 8152.5469026556. The cubic root of 66464021 is about 405.0688720957.

The spelling of 66464021 in words is "sixty-six million, four hundred sixty-four thousand, twenty-one".