66544013 has 2 divisors, whose sum is σ = 66544014. Its totient is φ = 66544012.

The previous prime is 66544003. The next prime is 66544021. The reversal of 66544013 is 31044566.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66227044 + 316969 = 8138^2 + 563^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66544013 is a prime.

It is a super-2 number, since 2×66544013² = 8856211332288338, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66544003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33272006 + 33272007.

It is an arithmetic number, because the mean of its divisors is an integer number (33272007).

Almost surely, 2^66544013 is an apocalyptic number.

It is an amenable number.

66544013 is a deficient number, since it is larger than the sum of its proper divisors (1).

66544013 is an equidigital number, since it uses as much as digits as its factorization.

66544013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 66544013 is about 8157.4513789541. The cubic root of 66544013 is about 405.2313122565.

Adding to 66544013 its reverse (31044566), we get a palindrome (97588579).

It can be divided in two parts, 665440 and 13, that multiplied together give a triangular number (8650720 = T₄₁₅₉).

The spelling of 66544013 in words is "sixty-six million, five hundred forty-four thousand, thirteen".