61666666840 has 32 divisors (see below), whose sum is σ = 139289906880. Its totient is φ = 24570683392.

The previous prime is 61666666829. The next prime is 61666666843. The reversal of 61666666840 is 4866666616.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61666666843) 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, 2989072 + ... + 3009631.

It is an arithmetic number, because the mean of its divisors is an integer number (4352809590).

Almost surely, 2^61666666840 is an apocalyptic number.

It is an amenable number.

61666666840 is an abundant number, since it is smaller than the sum of its proper divisors (77623240040).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61666666840 is a wasteful number, since it uses less digits than its factorization.

61666666840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5998971 (or 5998967 counting only the distinct ones).

The product of its (nonzero) digits is 8957952, while the sum is 55.

The spelling of 61666666840 in words is "sixty-one billion, six hundred sixty-six million, six hundred sixty-six thousand, eight hundred forty".