21071930 has 16 divisors (see below), whose sum is σ = 41377824. Its totient is φ = 7662480.

The previous prime is 21071927. The next prime is 21071977. The reversal of 21071930 is 3917012.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21071896 and 21071905.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 95672 + ... + 95891.

It is an arithmetic number, because the mean of its divisors is an integer number (2586114).

Almost surely, 2^21071930 is an apocalyptic number.

21071930 is a deficient number, since it is larger than the sum of its proper divisors (20305894).

21071930 is a wasteful number, since it uses less digits than its factorization.

21071930 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191581.

The product of its (nonzero) digits is 378, while the sum is 23.

The square root of 21071930 is about 4590.4171923693. The cubic root of 21071930 is about 276.2070577450.

Adding to 21071930 its reverse (3917012), we get a palindrome (24988942).

The spelling of 21071930 in words is "twenty-one million, seventy-one thousand, nine hundred thirty".