21021682 has 16 divisors (see below), whose sum is σ = 34736832. Its totient is φ = 9461520.

The previous prime is 21021667. The next prime is 21021683. The reversal of 21021682 is 28612012.

It is a super-2 number, since 2×21021682² = 883822228218248, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (21021683) by changing a digit.

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, 2373 + ... + 6904.

It is an arithmetic number, because the mean of its divisors is an integer number (2171052).

Almost surely, 2^21021682 is an apocalyptic number.

21021682 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21021682 is a deficient number, since it is larger than the sum of its proper divisors (13715150).

21021682 is a wasteful number, since it uses less digits than its factorization.

21021682 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9393.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 21021682 is about 4584.9407847866. The cubic root of 21021682 is about 275.9873357628.

Adding to 21021682 its reverse (28612012), we get a palindrome (49633694).

The spelling of 21021682 in words is "twenty-one million, twenty-one thousand, six hundred eighty-two".