61651688581 has 8 divisors (see below), whose sum is σ = 70461287424. Its totient is φ = 52842643440.

The previous prime is 61651688569. The next prime is 61651688597. The reversal of 61651688581 is 18588615616.

61651688581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61651688581 is a prime.

It is a super-2 number, since 2×61651688581² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61651688551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 136611 + ... + 376783.

It is an arithmetic number, because the mean of its divisors is an integer number (8807660928).

Almost surely, 2^61651688581 is an apocalyptic number.

It is an amenable number.

61651688581 is a deficient number, since it is larger than the sum of its proper divisors (8809598843).

61651688581 is a wasteful number, since it uses less digits than its factorization.

61651688581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276851.

The product of its digits is 2764800, while the sum is 55.

The spelling of 61651688581 in words is "sixty-one billion, six hundred fifty-one million, six hundred eighty-eight thousand, five hundred eighty-one".