66739980 has 24 divisors (see below), whose sum is σ = 186872112. Its totient is φ = 17797312.

The previous prime is 66739969. The next prime is 66740021. The reversal of 66739980 is 8993766.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 556107 + ... + 556226.

It is an arithmetic number, because the mean of its divisors is an integer number (7786338).

Almost surely, 2^66739980 is an apocalyptic number.

66739980 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66739980 is an abundant number, since it is smaller than the sum of its proper divisors (120132132).

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

66739980 is a wasteful number, since it uses less digits than its factorization.

66739980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1112345 (or 1112343 counting only the distinct ones).

The product of its (nonzero) digits is 489888, while the sum is 48.

The square root of 66739980 is about 8169.4540821281. The cubic root of 66739980 is about 405.6287140874.

It can be divided in two parts, 6673 and 9980, that added together give a triangular number (16653 = T₁₈₂).

The spelling of 66739980 in words is "sixty-six million, seven hundred thirty-nine thousand, nine hundred eighty".