21219897 has 8 divisors (see below), whose sum is σ = 28450240. Its totient is φ = 14068080.

The previous prime is 21219883. The next prime is 21219901. The reversal of 21219897 is 79891212.

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

It is not a de Polignac number, because 21219897 - 2⁸ = 21219641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21219857) 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, 18997 + ... + 20082.

It is an arithmetic number, because the mean of its divisors is an integer number (3556280).

Almost surely, 2^21219897 is an apocalyptic number.

It is an amenable number.

21219897 is a deficient number, since it is larger than the sum of its proper divisors (7230343).

21219897 is a wasteful number, since it uses less digits than its factorization.

21219897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39263.

The product of its digits is 18144, while the sum is 39.

The square root of 21219897 is about 4606.5059426858. The cubic root of 21219897 is about 276.8520586107.

The spelling of 21219897 in words is "twenty-one million, two hundred nineteen thousand, eight hundred ninety-seven".