61107135721 has 2 divisors, whose sum is σ = 61107135722. Its totient is φ = 61107135720.

The previous prime is 61107135709. The next prime is 61107135757. The reversal of 61107135721 is 12753170116.

It is a happy number.

61107135721 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., 42273416025 + 18833719696 = 205605^2 + 137236^2 .

It is a cyclic number.

It is not a de Polignac number, because 61107135721 - 2¹¹ = 61107133673 is a prime.

It is not a weakly prime, because it can be changed into another prime (61107135421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30553567860 + 30553567861.

It is an arithmetic number, because the mean of its divisors is an integer number (30553567861).

Almost surely, 2^61107135721 is an apocalyptic number.

It is an amenable number.

61107135721 is a deficient number, since it is larger than the sum of its proper divisors (1).

61107135721 is an equidigital number, since it uses as much as digits as its factorization.

61107135721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8820, while the sum is 34.

The spelling of 61107135721 in words is "sixty-one billion, one hundred seven million, one hundred thirty-five thousand, seven hundred twenty-one".