20781982 has 8 divisors (see below), whose sum is σ = 33570936. Its totient is φ = 9591672.

The previous prime is 20781931. The next prime is 20782031. The reversal of 20781982 is 28918702.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 399628 + ... + 399679.

It is an arithmetic number, because the mean of its divisors is an integer number (4196367).

Almost surely, 2^20781982 is an apocalyptic number.

20781982 is a deficient number, since it is larger than the sum of its proper divisors (12788954).

20781982 is a wasteful number, since it uses less digits than its factorization.

20781982 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 799322.

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

The square root of 20781982 is about 4558.7259184996. The cubic root of 20781982 is about 274.9343402470.

The spelling of 20781982 in words is "twenty million, seven hundred eighty-one thousand, nine hundred eighty-two".