21982642 has 16 divisors (see below), whose sum is σ = 36850464. Its totient is φ = 9748000.

The previous prime is 21982637. The next prime is 21982643. The reversal of 21982642 is 24628912.

It is a junction number, because it is equal to n+sod(n) for n = 21982598 and 21982607.

It is not an unprimeable number, because it can be changed into a prime (21982643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11284 + ... + 13087.

It is an arithmetic number, because the mean of its divisors is an integer number (2303154).

Almost surely, 2^21982642 is an apocalyptic number.

21982642 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21982642 is a deficient number, since it is larger than the sum of its proper divisors (14867822).

21982642 is a wasteful number, since it uses less digits than its factorization.

21982642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24425.

The product of its digits is 13824, while the sum is 34.

The square root of 21982642 is about 4688.5650256768. The cubic root of 21982642 is about 280.1302200412.

The spelling of 21982642 in words is "twenty-one million, nine hundred eighty-two thousand, six hundred forty-two".