21401066 has 8 divisors (see below), whose sum is σ = 32123520. Its totient is φ = 10693228.

The previous prime is 21401053. The next prime is 21401069. The reversal of 21401066 is 66010412.

It is a happy number.

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 (21401069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1415 + ... + 6693.

It is an arithmetic number, because the mean of its divisors is an integer number (4015440).

Almost surely, 2^21401066 is an apocalyptic number.

21401066 is a deficient number, since it is larger than the sum of its proper divisors (10722454).

21401066 is a wasteful number, since it uses less digits than its factorization.

21401066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7308.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 21401066 is about 4626.1286190507. The cubic root of 21401066 is about 277.6377196985.

Adding to 21401066 its reverse (66010412), we get a palindrome (87411478).

The spelling of 21401066 in words is "twenty-one million, four hundred one thousand, sixty-six".