21748329 has 12 divisors (see below), whose sum is σ = 32428032. Its totient is φ = 14031000.

The previous prime is 21748313. The next prime is 21748333. The reversal of 21748329 is 92384712.

It is not a de Polignac number, because 21748329 - 2⁴ = 21748313 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21748293 and 21748302.

It is not an unprimeable number, because it can be changed into a prime (21748399) 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, 38697 + ... + 39254.

It is an arithmetic number, because the mean of its divisors is an integer number (2702336).

Almost surely, 2^21748329 is an apocalyptic number.

It is an amenable number.

21748329 is a deficient number, since it is larger than the sum of its proper divisors (10679703).

21748329 is a wasteful number, since it uses less digits than its factorization.

21748329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77988 (or 77985 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 21748329 is about 4663.5103730988. The cubic root of 21748329 is about 279.1313598872.

The spelling of 21748329 in words is "twenty-one million, seven hundred forty-eight thousand, three hundred twenty-nine".