66381990 has 32 divisors (see below), whose sum is σ = 159549696. Its totient is φ = 17676000.

The previous prime is 66381967. The next prime is 66382007. The reversal of 66381990 is 9918366.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28365 + ... + 30615.

It is an arithmetic number, because the mean of its divisors is an integer number (4985928).

Almost surely, 2^66381990 is an apocalyptic number.

66381990 is an abundant number, since it is smaller than the sum of its proper divisors (93167706).

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

66381990 is a wasteful number, since it uses less digits than its factorization.

66381990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3244.

The product of its (nonzero) digits is 69984, while the sum is 42.

The square root of 66381990 is about 8147.5143448784. The cubic root of 66381990 is about 404.9021559095.

The spelling of 66381990 in words is "sixty-six million, three hundred eighty-one thousand, nine hundred ninety".