61281666556 has 48 divisors (see below), whose sum is σ = 118462393728. Its totient is φ = 27505620800.

The previous prime is 61281666553. The next prime is 61281666559. The reversal of 61281666556 is 65566618216.

It is an interprime number because it is at equal distance from previous prime (61281666553) and next prime (61281666559).

It is a super-2 number, since 2×61281666556² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61281666553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10993386 + ... + 10998958.

It is an arithmetic number, because the mean of its divisors is an integer number (2467966536).

Almost surely, 2^61281666556 is an apocalyptic number.

It is an amenable number.

61281666556 is a deficient number, since it is larger than the sum of its proper divisors (57180727172).

61281666556 is a wasteful number, since it uses less digits than its factorization.

61281666556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8682 (or 8680 counting only the distinct ones).

The product of its digits is 3110400, while the sum is 52.

The spelling of 61281666556 in words is "sixty-one billion, two hundred eighty-one million, six hundred sixty-six thousand, five hundred fifty-six".