21798427 has 8 divisors (see below), whose sum is σ = 25006592. Its totient is φ = 18613800.

The previous prime is 21798421. The next prime is 21798449. The reversal of 21798427 is 72489712.

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

It is a cyclic number.

It is not a de Polignac number, because 21798427 - 2³ = 21798419 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21798427.

It is not an unprimeable number, because it can be changed into a prime (21798421) 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 7 ways as a sum of consecutive naturals, for example, 3849 + ... + 7642.

It is an arithmetic number, because the mean of its divisors is an integer number (3125824).

Almost surely, 2^21798427 is an apocalyptic number.

21798427 is a deficient number, since it is larger than the sum of its proper divisors (3208165).

21798427 is a wasteful number, since it uses less digits than its factorization.

21798427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11769.

The product of its digits is 56448, while the sum is 40.

The square root of 21798427 is about 4668.8785591403. The cubic root of 21798427 is about 279.3455249864.

The spelling of 21798427 in words is "twenty-one million, seven hundred ninety-eight thousand, four hundred twenty-seven".