21749208 has 32 divisors (see below), whose sum is σ = 58556400. Its totient is φ = 6691968.

The previous prime is 21749207. The next prime is 21749213. The reversal of 21749208 is 80294712.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21749201) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34543 + ... + 35166.

Almost surely, 2^21749208 is an apocalyptic number.

It is an amenable number.

21749208 is an abundant number, since it is smaller than the sum of its proper divisors (36807192).

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

21749208 is a wasteful number, since it uses less digits than its factorization.

21749208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69731 (or 69727 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 21749208 is about 4663.6046144586. The cubic root of 21749208 is about 279.1351203778.

The spelling of 21749208 in words is "twenty-one million, seven hundred forty-nine thousand, two hundred eight".