61113412721 has 4 divisors (see below), whose sum is σ = 61115934372. Its totient is φ = 61110891072.

The previous prime is 61113412669. The next prime is 61113412729. The reversal of 61113412721 is 12721431116.

61113412721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 29894410000 + 31219002721 = 172900^2 + 176689^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61113412721 is a prime.

It is a super-4 number, since 4×61113412721⁴ (a number of 44 digits) contains 4444 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (61113412729) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1224116 + ... + 1273061.

It is an arithmetic number, because the mean of its divisors is an integer number (15278983593).

Almost surely, 2^61113412721 is an apocalyptic number.

It is an amenable number.

61113412721 is a deficient number, since it is larger than the sum of its proper divisors (2521651).

61113412721 is a wasteful number, since it uses less digits than its factorization.

61113412721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2521650.

The product of its digits is 2016, while the sum is 29.

Adding to 61113412721 its reverse (12721431116), we get a palindrome (73834843837).

The spelling of 61113412721 in words is "sixty-one billion, one hundred thirteen million, four hundred twelve thousand, seven hundred twenty-one".