21829520 has 40 divisors (see below), whose sum is σ = 50963256. Its totient is φ = 8695808.

The previous prime is 21829501. The next prime is 21829529. The reversal of 21829520 is 2592812.

It can be written as a sum of positive squares in 4 ways, for example, as 1936 + 21827584 = 44^2 + 4672^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (21829529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27854 + ... + 28626.

Almost surely, 2^21829520 is an apocalyptic number.

21829520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21829520 is an abundant number, since it is smaller than the sum of its proper divisors (29133736).

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

21829520 is a wasteful number, since it uses less digits than its factorization.

21829520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1139 (or 1133 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 21829520 is about 4672.2071871868. The cubic root of 21829520 is about 279.4782801917.

The spelling of 21829520 in words is "twenty-one million, eight hundred twenty-nine thousand, five hundred twenty".