21100642 has 8 divisors (see below), whose sum is σ = 32187600. Its totient is φ = 10371444.

The previous prime is 21100631. The next prime is 21100649. The reversal of 21100642 is 24600112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21100649) 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 3 ways as a sum of consecutive naturals, for example, 89292 + ... + 89527.

It is an arithmetic number, because the mean of its divisors is an integer number (4023450).

Almost surely, 2^21100642 is an apocalyptic number.

21100642 is a deficient number, since it is larger than the sum of its proper divisors (11086958).

21100642 is a wasteful number, since it uses less digits than its factorization.

21100642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178880.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21100642 is about 4593.5435123660. The cubic root of 21100642 is about 276.3324513821.

Adding to 21100642 its reverse (24600112), we get a palindrome (45700754).

The spelling of 21100642 in words is "twenty-one million, one hundred thousand, six hundred forty-two".