661780108 has 48 divisors (see below), whose sum is σ = 1352534400. Its totient is φ = 280126080.

The previous prime is 661780099. The next prime is 661780117. The reversal of 661780108 is 801087166.

It is an interprime number because it is at equal distance from previous prime (661780099) and next prime (661780117).

It is a super-2 number, since 2×661780108² = 875905822688983328, which contains 22 as substring.

It is an unprimeable number.

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, 42616 + ... + 56032.

It is an arithmetic number, because the mean of its divisors is an integer number (28177800).

Almost surely, 2^661780108 is an apocalyptic number.

It is an amenable number.

661780108 is an abundant number, since it is smaller than the sum of its proper divisors (690754292).

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

661780108 is a wasteful number, since it uses less digits than its factorization.

661780108 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13510 (or 13508 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 661780108 is about 25725.0871329914. The cubic root of 661780108 is about 871.4408273625.

The spelling of 661780108 in words is "six hundred sixty-one million, seven hundred eighty thousand, one hundred eight".