201553721 has 2 divisors, whose sum is σ = 201553722. Its totient is φ = 201553720.

The previous prime is 201553711. The next prime is 201553739. The reversal of 201553721 is 127355102.

201553721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 201498025 + 55696 = 14195^2 + 236^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201553721 is a prime.

It is not a weakly prime, because it can be changed into another prime (201553711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100776860 + 100776861.

It is an arithmetic number, because the mean of its divisors is an integer number (100776861).

Almost surely, 2^201553721 is an apocalyptic number.

It is an amenable number.

201553721 is a deficient number, since it is larger than the sum of its proper divisors (1).

201553721 is an equidigital number, since it uses as much as digits as its factorization.

201553721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2100, while the sum is 26.

The square root of 201553721 is about 14196.9616819938. The cubic root of 201553721 is about 586.3140122228.

The spelling of 201553721 in words is "two hundred one million, five hundred fifty-three thousand, seven hundred twenty-one".