21793420 has 96 divisors (see below), whose sum is σ = 53706240. Its totient is φ = 7349760.

The previous prime is 21793363. The next prime is 21793451. The reversal of 21793420 is 2439712.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 298504 + ... + 298576.

It is an arithmetic number, because the mean of its divisors is an integer number (559440).

Almost surely, 2^21793420 is an apocalyptic number.

21793420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21793420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26853120).

21793420 is an abundant number, since it is smaller than the sum of its proper divisors (31912820).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21793420 is a wasteful number, since it uses less digits than its factorization.

21793420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175 (or 173 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21793420 is about 4668.3423182110. The cubic root of 21793420 is about 279.3241352144.

The spelling of 21793420 in words is "twenty-one million, seven hundred ninety-three thousand, four hundred twenty".