721442101 has 2 divisors, whose sum is σ = 721442102. Its totient is φ = 721442100.

The previous prime is 721442087. The next prime is 721442143. The reversal of 721442101 is 101244127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 696432100 + 25010001 = 26390^2 + 5001^2 .

It is an emirp because it is prime and its reverse (101244127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721442101 - 2⁵ = 721442069 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721412101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360721050 + 360721051.

It is an arithmetic number, because the mean of its divisors is an integer number (360721051).

Almost surely, 2^721442101 is an apocalyptic number.

It is an amenable number.

721442101 is a deficient number, since it is larger than the sum of its proper divisors (1).

721442101 is an equidigital number, since it uses as much as digits as its factorization.

721442101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 721442101 is about 26859.6742534231. The cubic root of 721442101 is about 896.8789426771.

Adding to 721442101 its reverse (101244127), we get a palindrome (822686228).

The spelling of 721442101 in words is "seven hundred twenty-one million, four hundred forty-two thousand, one hundred one".