21928311 has 6 divisors (see below), whose sum is σ = 31674240. Its totient is φ = 14618868.

The previous prime is 21928303. The next prime is 21928327. The reversal of 21928311 is 11382912.

It is not a de Polignac number, because 21928311 - 2³ = 21928303 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21928301) 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, 1218231 + ... + 1218248.

It is an arithmetic number, because the mean of its divisors is an integer number (5279040).

Almost surely, 2^21928311 is an apocalyptic number.

21928311 is a deficient number, since it is larger than the sum of its proper divisors (9745929).

21928311 is a wasteful number, since it uses less digits than its factorization.

21928311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2436485 (or 2436482 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 21928311 is about 4682.7674509845. The cubic root of 21928311 is about 279.8992452115.

The spelling of 21928311 in words is "twenty-one million, nine hundred twenty-eight thousand, three hundred eleven".