21455938 has 24 divisors (see below), whose sum is σ = 39079872. Its totient is φ = 8652864.

The previous prime is 21455933. The next prime is 21455939. The reversal of 21455938 is 83955412.

It is a junction number, because it is equal to n+sod(n) for n = 21455897 and 21455906.

It is not an unprimeable number, because it can be changed into a prime (21455933) 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, 1395 + ... + 6697.

It is an arithmetic number, because the mean of its divisors is an integer number (1628328).

Almost surely, 2^21455938 is an apocalyptic number.

21455938 is a deficient number, since it is larger than the sum of its proper divisors (17623934).

21455938 is a wasteful number, since it uses less digits than its factorization.

21455938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5346 (or 5329 counting only the distinct ones).

The product of its digits is 43200, while the sum is 37.

The square root of 21455938 is about 4632.0554832601. The cubic root of 21455938 is about 277.8748034509.

The spelling of 21455938 in words is "twenty-one million, four hundred fifty-five thousand, nine hundred thirty-eight".