61720397 has 2 divisors, whose sum is σ = 61720398. Its totient is φ = 61720396.

The previous prime is 61720369. The next prime is 61720423. The reversal of 61720397 is 79302716.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42237001 + 19483396 = 6499^2 + 4414^2 .

It is a cyclic number.

It is not a de Polignac number, because 61720397 - 2¹⁶ = 61654861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61725397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30860198 + 30860199.

It is an arithmetic number, because the mean of its divisors is an integer number (30860199).

Almost surely, 2^61720397 is an apocalyptic number.

It is an amenable number.

61720397 is a deficient number, since it is larger than the sum of its proper divisors (1).

61720397 is an equidigital number, since it uses as much as digits as its factorization.

61720397 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15876, while the sum is 35.

The square root of 61720397 is about 7856.2330031638. The cubic root of 61720397 is about 395.1932974770.

The spelling of 61720397 in words is "sixty-one million, seven hundred twenty thousand, three hundred ninety-seven".