21005922 has 32 divisors (see below), whose sum is σ = 48190464. Its totient is φ = 5979600.

The previous prime is 21005903. The next prime is 21005953. The reversal of 21005922 is 22950012.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13147 + ... + 14657.

It is an arithmetic number, because the mean of its divisors is an integer number (1505952).

Almost surely, 2^21005922 is an apocalyptic number.

21005922 is an abundant number, since it is smaller than the sum of its proper divisors (27184542).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21005922 is a wasteful number, since it uses less digits than its factorization.

21005922 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1854.

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 21005922 is about 4583.2217925822. The cubic root of 21005922 is about 275.9183490880.

Adding to 21005922 its reverse (22950012), we get a palindrome (43955934).

The spelling of 21005922 in words is "twenty-one million, five thousand, nine hundred twenty-two".