61721549 has 2 divisors, whose sum is σ = 61721550. Its totient is φ = 61721548.

The previous prime is 61721533. The next prime is 61721563. The reversal of 61721549 is 94512716.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50665924 + 11055625 = 7118^2 + 3325^2 .

It is a cyclic number.

It is not a de Polignac number, because 61721549 - 2⁴ = 61721533 is a prime.

It is a super-2 number, since 2×61721549² = 7619099221918802, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61721449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30860774 + 30860775.

It is an arithmetic number, because the mean of its divisors is an integer number (30860775).

Almost surely, 2^61721549 is an apocalyptic number.

It is an amenable number.

61721549 is a deficient number, since it is larger than the sum of its proper divisors (1).

61721549 is an equidigital number, since it uses as much as digits as its factorization.

61721549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15120, while the sum is 35.

The square root of 61721549 is about 7856.3063204027. The cubic root of 61721549 is about 395.1957561987.

The spelling of 61721549 in words is "sixty-one million, seven hundred twenty-one thousand, five hundred forty-nine".