21874329 has 9 divisors (see below), whose sum is σ = 31616533. Its totient is φ = 14573532.

The previous prime is 21874327. The next prime is 21874367. The reversal of 21874329 is 92347812.

The square root of 21874329 is 4677.

It is a perfect power (a square), and thus also a powerful number.

21874329 is a `hidden beast` number, since 218 + 7 + 432 + 9 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 21874329 - 2¹ = 21874327 is a prime.

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

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21874293 and 21874302.

It is not an unprimeable number, because it can be changed into a prime (21874327) 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 8 ways as a sum of consecutive naturals, for example, 13252 + ... + 14810.

Almost surely, 2^21874329 is an apocalyptic number.

21874329 is the 4677-th square number.

21874329 is the 2339-th centered octagonal number.

It is an amenable number.

21874329 is a deficient number, since it is larger than the sum of its proper divisors (9742204).

21874329 is an frugal number, since it uses more digits than its factorization.

21874329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3124 (or 1562 counting only the distinct ones).

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

The cubic root of 21874329 is about 279.6693759091.

Multiplying 21874329 by its sum of digits (36), we get a square (787475844 = 28062²).

It can be divided in two parts, 2187432 and 9, that added together give a square (2187441 = 1479²).

The spelling of 21874329 in words is "twenty-one million, eight hundred seventy-four thousand, three hundred twenty-nine".