21829518 has 96 divisors (see below), whose sum is σ = 53913600. Its totient is φ = 6350400.

The previous prime is 21829501. The next prime is 21829529. The reversal of 21829518 is 81592812.

It is a super-2 number, since 2×21829518² = 953055712224648, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 307423 + ... + 307493.

It is an arithmetic number, because the mean of its divisors is an integer number (561600).

Almost surely, 2^21829518 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21829518, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26956800).

21829518 is an abundant number, since it is smaller than the sum of its proper divisors (32084082).

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

21829518 is a wasteful number, since it uses less digits than its factorization.

21829518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158 (or 155 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 21829518 is about 4672.2069731552. The cubic root of 21829518 is about 279.4782716566.

The spelling of 21829518 in words is "twenty-one million, eight hundred twenty-nine thousand, five hundred eighteen".