20781442 has 16 divisors (see below), whose sum is σ = 34119072. Its totient is φ = 9414720.

The previous prime is 20781437. The next prime is 20781451. The reversal of 20781442 is 24418702.

It is a self number, because there is not a number n which added to its sum of digits gives 20781442.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6013 + ... + 8815.

It is an arithmetic number, because the mean of its divisors is an integer number (2132442).

Almost surely, 2^20781442 is an apocalyptic number.

20781442 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

20781442 is a deficient number, since it is larger than the sum of its proper divisors (13337630).

20781442 is a wasteful number, since it uses less digits than its factorization.

20781442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3153.

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 20781442 is about 4558.6666910403. Note that the first 4 decimals coincide. The cubic root of 20781442 is about 274.9319589241.

The spelling of 20781442 in words is "twenty million, seven hundred eighty-one thousand, four hundred forty-two".