21797247 has 24 divisors (see below), whose sum is σ = 31908352. Its totient is φ = 13219200.

The previous prime is 21797233. The next prime is 21797249. The reversal of 21797247 is 74279712.

It is not a de Polignac number, because 21797247 - 2⁷ = 21797119 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21797249) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26472 + ... + 27282.

Almost surely, 2^21797247 is an apocalyptic number.

21797247 is a deficient number, since it is larger than the sum of its proper divisors (10111105).

21797247 is a wasteful number, since it uses less digits than its factorization.

21797247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 879 (or 862 counting only the distinct ones).

The product of its digits is 49392, while the sum is 39.

The square root of 21797247 is about 4668.7521887545. The cubic root of 21797247 is about 279.3404843525.

The spelling of 21797247 in words is "twenty-one million, seven hundred ninety-seven thousand, two hundred forty-seven".