721714661 has 2 divisors, whose sum is σ = 721714662. Its totient is φ = 721714660.

The previous prime is 721714649. The next prime is 721714667. The reversal of 721714661 is 166417127.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 538518436 + 183196225 = 23206^2 + 13535^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721714661 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721714667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360857330 + 360857331.

It is an arithmetic number, because the mean of its divisors is an integer number (360857331).

Almost surely, 2^721714661 is an apocalyptic number.

It is an amenable number.

721714661 is a deficient number, since it is larger than the sum of its proper divisors (1).

721714661 is an equidigital number, since it uses as much as digits as its factorization.

721714661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14112, while the sum is 35.

The square root of 721714661 is about 26864.7475513916. The cubic root of 721714661 is about 896.9918750691.

The spelling of 721714661 in words is "seven hundred twenty-one million, seven hundred fourteen thousand, six hundred sixty-one".