21420934 has 8 divisors (see below), whose sum is σ = 32276160. Its totient is φ = 10662216.

The previous prime is 21420887. The next prime is 21420941. The reversal of 21420934 is 43902412.

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

It is a junction number, because it is equal to n+sod(n) for n = 21420899 and 21420908.

It is a congruent number.

It is an unprimeable number.

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, 23569 + ... + 24460.

It is an arithmetic number, because the mean of its divisors is an integer number (4034520).

Almost surely, 2^21420934 is an apocalyptic number.

21420934 is a deficient number, since it is larger than the sum of its proper divisors (10855226).

21420934 is a wasteful number, since it uses less digits than its factorization.

21420934 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48254.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 21420934 is about 4628.2754887755. The cubic root of 21420934 is about 277.7236095027.

The spelling of 21420934 in words is "twenty-one million, four hundred twenty thousand, nine hundred thirty-four".