21044690 has 16 divisors (see below), whose sum is σ = 37953792. Its totient is φ = 8401584.

The previous prime is 21044687. The next prime is 21044711. The reversal of 21044690 is 9644012.

It is a super-2 number, since 2×21044690² = 885757954392200, which contains 22 as substring.

It is an unprimeable number.

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, 4337 + ... + 7803.

It is an arithmetic number, because the mean of its divisors is an integer number (2372112).

Almost surely, 2^21044690 is an apocalyptic number.

21044690 is a deficient number, since it is larger than the sum of its proper divisors (16909102).

21044690 is a wasteful number, since it uses less digits than its factorization.

21044690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4081.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 21044690 is about 4587.4491822798. The cubic root of 21044690 is about 276.0879874200.

The spelling of 21044690 in words is "twenty-one million, forty-four thousand, six hundred ninety".