4621720661 has 2 divisors, whose sum is σ = 4621720662. Its totient is φ = 4621720660.

The previous prime is 4621720639. The next prime is 4621720687. The reversal of 4621720661 is 1660271264.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2871888100 + 1749832561 = 53590^2 + 41831^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4621720661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4621722661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2310860330 + 2310860331.

It is an arithmetic number, because the mean of its divisors is an integer number (2310860331).

Almost surely, 2^4621720661 is an apocalyptic number.

It is an amenable number.

4621720661 is a deficient number, since it is larger than the sum of its proper divisors (1).

4621720661 is an equidigital number, since it uses as much as digits as its factorization.

4621720661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 35.

The square root of 4621720661 is about 67983.2380885171. The cubic root of 4621720661 is about 1665.7170494702.

The spelling of 4621720661 in words is "four billion, six hundred twenty-one million, seven hundred twenty thousand, six hundred sixty-one".