721253653 has 2 divisors, whose sum is σ = 721253654. Its totient is φ = 721253652.

The previous prime is 721253639. The next prime is 721253669. The reversal of 721253653 is 356352127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 716204644 + 5049009 = 26762^2 + 2247^2 .

It is a cyclic number.

It is not a de Polignac number, because 721253653 - 2¹³ = 721245461 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721253633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360626826 + 360626827.

It is an arithmetic number, because the mean of its divisors is an integer number (360626827).

Almost surely, 2^721253653 is an apocalyptic number.

It is an amenable number.

721253653 is a deficient number, since it is larger than the sum of its proper divisors (1).

721253653 is an equidigital number, since it uses as much as digits as its factorization.

721253653 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37800, while the sum is 34.

The square root of 721253653 is about 26856.1660145301. The cubic root of 721253653 is about 896.8008445821.

The spelling of 721253653 in words is "seven hundred twenty-one million, two hundred fifty-three thousand, six hundred fifty-three".