20781006 has 16 divisors (see below), whose sum is σ = 43369344. Its totient is φ = 6625784.

The previous prime is 20780999. The next prime is 20781017. The reversal of 20781006 is 60018702.

It is a congruent 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, 75156 + ... + 75431.

It is an arithmetic number, because the mean of its divisors is an integer number (2710584).

Almost surely, 2^20781006 is an apocalyptic number.

20781006 is an abundant number, since it is smaller than the sum of its proper divisors (22588338).

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

20781006 is a wasteful number, since it uses less digits than its factorization.

20781006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150615.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 20781006 is about 4558.6188697894. The cubic root of 20781006 is about 274.9300361962.

Adding to 20781006 its reverse (60018702), we get a palindrome (80799708).

Subtracting 20781006 from its reverse (60018702), we obtain a square (39237696 = 6264²).

The spelling of 20781006 in words is "twenty million, seven hundred eighty-one thousand, six".