721011553 has 2 divisors, whose sum is σ = 721011554. Its totient is φ = 721011552.

The previous prime is 721011541. The next prime is 721011569. The reversal of 721011553 is 355110127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 718615249 + 2396304 = 26807^2 + 1548^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721011553 is a prime.

It is not a weakly prime, because it can be changed into another prime (721011593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360505776 + 360505777.

It is an arithmetic number, because the mean of its divisors is an integer number (360505777).

Almost surely, 2^721011553 is an apocalyptic number.

It is an amenable number.

721011553 is a deficient number, since it is larger than the sum of its proper divisors (1).

721011553 is an equidigital number, since it uses as much as digits as its factorization.

721011553 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1050, while the sum is 25.

The square root of 721011553 is about 26851.6582914352. The cubic root of 721011553 is about 896.7004916384.

The spelling of 721011553 in words is "seven hundred twenty-one million, eleven thousand, five hundred fifty-three".