21020782 has 16 divisors (see below), whose sum is σ = 32432400. Its totient is φ = 10212160.

The previous prime is 21020777. The next prime is 21020803. The reversal of 21020782 is 28702012.

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, 31569 + ... + 32227.

It is an arithmetic number, because the mean of its divisors is an integer number (2027025).

Almost surely, 2^21020782 is an apocalyptic number.

21020782 is a deficient number, since it is larger than the sum of its proper divisors (11411618).

21020782 is a wasteful number, since it uses less digits than its factorization.

21020782 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1091.

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 21020782 is about 4584.8426363399. The cubic root of 21020782 is about 275.9833970969.

Adding to 21020782 its reverse (28702012), we get a palindrome (49722794).

The spelling of 21020782 in words is "twenty-one million, twenty thousand, seven hundred eighty-two".