20911928 has 8 divisors (see below), whose sum is σ = 39209880. Its totient is φ = 10455960.

The previous prime is 20911909. The next prime is 20911931. The reversal of 20911928 is 82911902.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 20911894 and 20911903.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1306988 + ... + 1307003.

It is an arithmetic number, because the mean of its divisors is an integer number (4901235).

Almost surely, 2^20911928 is an apocalyptic number.

It is an amenable number.

20911928 is a deficient number, since it is larger than the sum of its proper divisors (18297952).

20911928 is a wasteful number, since it uses less digits than its factorization.

20911928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2613997 (or 2613993 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 20911928 is about 4572.9561554863. The cubic root of 20911928 is about 275.5061883562.

The spelling of 20911928 in words is "twenty million, nine hundred eleven thousand, nine hundred twenty-eight".