6655721721701 has 16 divisors (see below), whose sum is σ = 7590048593904. Its totient is φ = 5781798779904.

The previous prime is 6655721721697. The next prime is 6655721721721. The reversal of 6655721721701 is 1071271275566.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 516674877601 + 6139046844100 = 718801^2 + 2477710^2 .

It is a cyclic number.

It is not a de Polignac number, because 6655721721701 - 2² = 6655721721697 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 6655721721701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6655721721721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 920951 + ... + 3762923.

It is an arithmetic number, because the mean of its divisors is an integer number (474378037119).

Almost surely, 2^{6655721721701} is an apocalyptic number.

It is an amenable number.

6655721721701 is a deficient number, since it is larger than the sum of its proper divisors (934326872203).

6655721721701 is a wasteful number, since it uses less digits than its factorization.

6655721721701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2852600.

The product of its (nonzero) digits is 1234800, while the sum is 50.

The spelling of 6655721721701 in words is "six trillion, six hundred fifty-five billion, seven hundred twenty-one million, seven hundred twenty-one thousand, seven hundred one".