21849904 has 20 divisors (see below), whose sum is σ = 42479176. Its totient is φ = 10887552.

The previous prime is 21849881. The next prime is 21849907. The reversal of 21849904 is 40994812.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21849907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2827 + ... + 7189.

Almost surely, 2^21849904 is an apocalyptic number.

It is an amenable number.

21849904 is a deficient number, since it is larger than the sum of its proper divisors (20629272).

21849904 is a wasteful number, since it uses less digits than its factorization.

21849904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4684 (or 4678 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 21849904 is about 4674.3880882956. The cubic root of 21849904 is about 279.5652436701.

The spelling of 21849904 in words is "twenty-one million, eight hundred forty-nine thousand, nine hundred four".