21838545 has 32 divisors (see below), whose sum is σ = 39312000. Its totient is φ = 11500992.

The previous prime is 21838519. The next prime is 21838561. The reversal of 21838545 is 54583812.

It is a happy number.

It is not a de Polignac number, because 21838545 - 2⁵ = 21838513 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10231 + ... + 12179.

It is an arithmetic number, because the mean of its divisors is an integer number (1228500).

Almost surely, 2^21838545 is an apocalyptic number.

It is an amenable number.

21838545 is a deficient number, since it is larger than the sum of its proper divisors (17473455).

21838545 is a wasteful number, since it uses less digits than its factorization.

21838545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2046 (or 2040 counting only the distinct ones).

The product of its digits is 38400, while the sum is 36.

The square root of 21838545 is about 4673.1729049972. The cubic root of 21838545 is about 279.5167898789.

The spelling of 21838545 in words is "twenty-one million, eight hundred thirty-eight thousand, five hundred forty-five".