21249324 has 48 divisors (see below), whose sum is σ = 55498240. Its totient is φ = 7030800.

The previous prime is 21249313. The next prime is 21249329. The reversal of 21249324 is 42394212.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21249329) 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 15 ways as a sum of consecutive naturals, for example, 15657 + ... + 16959.

Almost surely, 2^21249324 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21249324, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27749120).

21249324 is an abundant number, since it is smaller than the sum of its proper divisors (34248916).

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

21249324 is a wasteful number, since it uses less digits than its factorization.

21249324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1467 (or 1459 counting only the distinct ones).

The product of its digits is 3456, while the sum is 27.

The square root of 21249324 is about 4609.6989055686. The cubic root of 21249324 is about 276.9799757015.

The spelling of 21249324 in words is "twenty-one million, two hundred forty-nine thousand, three hundred twenty-four".