21022047 has 12 divisors (see below), whose sum is σ = 32151600. Its totient is φ = 13190208.

The previous prime is 21022021. The next prime is 21022049. The reversal of 21022047 is 74022012.

It is not a de Polignac number, because 21022047 - 2¹² = 21017951 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022049) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 68547 + ... + 68852.

It is an arithmetic number, because the mean of its divisors is an integer number (2679300).

Almost surely, 2^21022047 is an apocalyptic number.

21022047 is a deficient number, since it is larger than the sum of its proper divisors (11129553).

21022047 is a wasteful number, since it uses less digits than its factorization.

21022047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137422 (or 137419 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 21022047 is about 4584.9805888357. The cubic root of 21022047 is about 275.9889330786.

Adding to 21022047 its reverse (74022012), we get a palindrome (95044059).

The spelling of 21022047 in words is "twenty-one million, twenty-two thousand, forty-seven".