21242799 has 6 divisors (see below), whose sum is σ = 30684056. Its totient is φ = 14161860.

The previous prime is 21242789. The next prime is 21242803. The reversal of 21242799 is 99724212.

It is not a de Polignac number, because 21242799 - 2⁴ = 21242783 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 (21242729) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1180147 + ... + 1180164.

Almost surely, 2^21242799 is an apocalyptic number.

21242799 is a deficient number, since it is larger than the sum of its proper divisors (9441257).

21242799 is a wasteful number, since it uses less digits than its factorization.

21242799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2360317 (or 2360314 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 21242799 is about 4608.9911043524. The cubic root of 21242799 is about 276.9516221821.

The spelling of 21242799 in words is "twenty-one million, two hundred forty-two thousand, seven hundred ninety-nine".