61107721 has 2 divisors, whose sum is σ = 61107722. Its totient is φ = 61107720.

The previous prime is 61107703. The next prime is 61107733. The reversal of 61107721 is 12770116.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43560000 + 17547721 = 6600^2 + 4189^2 .

It is a cyclic number.

It is not a de Polignac number, because 61107721 - 2¹⁷ = 60976649 is a prime.

It is not a weakly prime, because it can be changed into another prime (61107751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30553860 + 30553861.

It is an arithmetic number, because the mean of its divisors is an integer number (30553861).

Almost surely, 2^61107721 is an apocalyptic number.

It is an amenable number.

61107721 is a deficient number, since it is larger than the sum of its proper divisors (1).

61107721 is an equidigital number, since it uses as much as digits as its factorization.

61107721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 588, while the sum is 25.

The square root of 61107721 is about 7817.1427644632. The cubic root of 61107721 is about 393.8812997578.

Adding to 61107721 its reverse (12770116), we get a palindrome (73877837).

It can be divided in two parts, 6110 and 7721, that added together give a palindrome (13831).

The spelling of 61107721 in words is "sixty-one million, one hundred seven thousand, seven hundred twenty-one".