21949538 has 16 divisors (see below), whose sum is σ = 35622720. Its totient is φ = 10083216.

The previous prime is 21949531. The next prime is 21949553. The reversal of 21949538 is 83594912.

It is a junction number, because it is equal to n+sod(n) for n = 21949495 and 21949504.

It is not an unprimeable number, because it can be changed into a prime (21949531) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 4043 + ... + 7761.

It is an arithmetic number, because the mean of its divisors is an integer number (2226420).

Almost surely, 2^21949538 is an apocalyptic number.

21949538 is a deficient number, since it is larger than the sum of its proper divisors (13673182).

21949538 is a wasteful number, since it uses less digits than its factorization.

21949538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3961.

The product of its digits is 77760, while the sum is 41.

The square root of 21949538 is about 4685.0334043633. The cubic root of 21949538 is about 279.9895319216.

The spelling of 21949538 in words is "twenty-one million, nine hundred forty-nine thousand, five hundred thirty-eight".