1661666010 has 64 divisors (see below), whose sum is σ = 4027000320. Its totient is φ = 438799680.

The previous prime is 1661665979. The next prime is 1661666011. The reversal of 1661666010 is 106661661.

It is a super-2 number, since 2×1661666010² = 5522267857578640200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1661666011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2048505 + ... + 2049315.

It is an arithmetic number, because the mean of its divisors is an integer number (62921880).

Almost surely, 2^1661666010 is an apocalyptic number.

1661666010 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1661666010 is an abundant number, since it is smaller than the sum of its proper divisors (2365334310).

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

1661666010 is a wasteful number, since it uses less digits than its factorization.

1661666010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1403.

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 1661666010 is about 40763.5377512796. The cubic root of 1661666010 is about 1184.4441267590. Note that the first 3 decimals are identical.

The spelling of 1661666010 in words is "one billion, six hundred sixty-one million, six hundred sixty-six thousand, ten".