66720544400501 has 4 divisors (see below), whose sum is σ = 67716373421472. Its totient is φ = 65724715379532.

The previous prime is 66720544400491. The next prime is 66720544400567. The reversal of 66720544400501 is 10500444502766.

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 a cyclic number.

It is not a de Polignac number, because 66720544400501 - 2¹⁸ = 66720544138357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66720544400581) 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, 497914510385 + ... + 497914510518.

It is an arithmetic number, because the mean of its divisors is an integer number (16929093355368).

Almost surely, 2^{66720544400501} is an apocalyptic number.

It is an amenable number.

66720544400501 is a deficient number, since it is larger than the sum of its proper divisors (995829020971).

66720544400501 is an equidigital number, since it uses as much as digits as its factorization.

66720544400501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 995829020970.

The product of its (nonzero) digits is 806400, while the sum is 44.

The spelling of 66720544400501 in words is "sixty-six trillion, seven hundred twenty billion, five hundred forty-four million, four hundred thousand, five hundred one".