720735121 has 2 divisors, whose sum is σ = 720735122. Its totient is φ = 720735120.

The previous prime is 720735101. The next prime is 720735137. The reversal of 720735121 is 121537027.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 684554896 + 36180225 = 26164^2 + 6015^2 .

It is a cyclic number.

It is not a de Polignac number, because 720735121 - 2²³ = 712346513 is a prime.

It is a super-2 number, since 2×720735121² = 1038918229285769282, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 720735121.

It is not a weakly prime, because it can be changed into another prime (720735101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360367560 + 360367561.

It is an arithmetic number, because the mean of its divisors is an integer number (360367561).

Almost surely, 2^720735121 is an apocalyptic number.

It is an amenable number.

720735121 is a deficient number, since it is larger than the sum of its proper divisors (1).

720735121 is an equidigital number, since it uses as much as digits as its factorization.

720735121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2940, while the sum is 28.

The square root of 720735121 is about 26846.5104063824. The cubic root of 720735121 is about 896.5858802547.

The spelling of 720735121 in words is "seven hundred twenty million, seven hundred thirty-five thousand, one hundred twenty-one".