21800397 has 8 divisors (see below), whose sum is σ = 29776320. Its totient is φ = 14179040.

The previous prime is 21800369. The next prime is 21800413. The reversal of 21800397 is 79300812.

It is a happy number.

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 21800397 - 2¹⁹ = 21276109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21800357) 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, 88497 + ... + 88742.

It is an arithmetic number, because the mean of its divisors is an integer number (3722040).

Almost surely, 2^21800397 is an apocalyptic number.

It is an amenable number.

21800397 is a deficient number, since it is larger than the sum of its proper divisors (7975923).

21800397 is a wasteful number, since it uses less digits than its factorization.

21800397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177283.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 21800397 is about 4669.0895258069. The cubic root of 21800397 is about 279.3539398766.

The spelling of 21800397 in words is "twenty-one million, eight hundred thousand, three hundred ninety-seven".