21929271 has 48 divisors (see below), whose sum is σ = 37384704. Its totient is φ = 11187072.

The previous prime is 21929267. The next prime is 21929293. The reversal of 21929271 is 17292912.

It is not a de Polignac number, because 21929271 - 2² = 21929267 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21929231) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 131230 + ... + 131396.

It is an arithmetic number, because the mean of its divisors is an integer number (778848).

Almost surely, 2^21929271 is an apocalyptic number.

21929271 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21929271 is a deficient number, since it is larger than the sum of its proper divisors (15455433).

21929271 is a wasteful number, since it uses less digits than its factorization.

21929271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 227 counting only the distinct ones).

The product of its digits is 4536, while the sum is 33.

The square root of 21929271 is about 4682.8699533513. The cubic root of 21929271 is about 279.9033297236.

The spelling of 21929271 in words is "twenty-one million, nine hundred twenty-nine thousand, two hundred seventy-one".