21178797 has 8 divisors (see below), whose sum is σ = 29149440. Its totient is φ = 13663680.

The previous prime is 21178793. The next prime is 21178813. The reversal of 21178797 is 79787112.

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

It is not a de Polignac number, because 21178797 - 2² = 21178793 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21178793) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 113772 + ... + 113957.

It is an arithmetic number, because the mean of its divisors is an integer number (3643680).

Almost surely, 2^21178797 is an apocalyptic number.

It is an amenable number.

21178797 is a deficient number, since it is larger than the sum of its proper divisors (7970643).

21178797 is a wasteful number, since it uses less digits than its factorization.

21178797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227763.

The product of its digits is 49392, while the sum is 42.

The square root of 21178797 is about 4602.0426986285. The cubic root of 21178797 is about 276.6732017295.

The spelling of 21178797 in words is "twenty-one million, one hundred seventy-eight thousand, seven hundred ninety-seven".