720122621 has 2 divisors, whose sum is σ = 720122622. Its totient is φ = 720122620.

The previous prime is 720122573. The next prime is 720122657. The reversal of 720122621 is 126221027.

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., 443565721 + 276556900 = 21061^2 + 16630^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-720122621 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (720122321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360061310 + 360061311.

It is an arithmetic number, because the mean of its divisors is an integer number (360061311).

Almost surely, 2^720122621 is an apocalyptic number.

It is an amenable number.

720122621 is a deficient number, since it is larger than the sum of its proper divisors (1).

720122621 is an equidigital number, since it uses as much as digits as its factorization.

720122621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 720122621 is about 26835.1005401508. The cubic root of 720122621 is about 896.3318273799.

Adding to 720122621 its reverse (126221027), we get a palindrome (846343648).

The spelling of 720122621 in words is "seven hundred twenty million, one hundred twenty-two thousand, six hundred twenty-one".