21402324 has 36 divisors (see below), whose sum is σ = 54264756. Its totient is φ = 7112448.

The previous prime is 21402323. The next prime is 21402331. The reversal of 21402324 is 42320412.

21402324 = T₇₂ + T₇₃ + ... + T₅₀₄.

It can be written as a sum of positive squares in 2 ways, for example, as 13176900 + 8225424 = 3630^2 + 2868^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21402297 and 21402306.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21402323) 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 11 ways as a sum of consecutive naturals, for example, 14902 + ... + 16274.

Almost surely, 2^21402324 is an apocalyptic number.

It is an amenable number.

21402324 is an abundant number, since it is smaller than the sum of its proper divisors (32862432).

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

21402324 is a wasteful number, since it uses less digits than its factorization.

21402324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1816 (or 1811 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 21402324 is about 4626.2645838733. The cubic root of 21402324 is about 277.6431596364.

Adding to 21402324 its reverse (42320412), we get a palindrome (63722736).

The spelling of 21402324 in words is "twenty-one million, four hundred two thousand, three hundred twenty-four".