21323340 has 36 divisors (see below), whose sum is σ = 64681344. Its totient is φ = 5686176.

The previous prime is 21323311. The next prime is 21323371. The reversal of 21323340 is 4332312.

21323340 is a `hidden beast` number, since 2 + 1 + 323 + 340 = 666.

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 an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 59052 + ... + 59411.

It is an arithmetic number, because the mean of its divisors is an integer number (1796704).

Almost surely, 2^21323340 is an apocalyptic number.

21323340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21323340 is an abundant number, since it is smaller than the sum of its proper divisors (43358004).

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

21323340 is a wasteful number, since it uses less digits than its factorization.

21323340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118478 (or 118473 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 18.

The square root of 21323340 is about 4617.7202167303. The cubic root of 21323340 is about 277.3011967868.

Adding to 21323340 its reverse (4332312), we get a palindrome (25655652).

The spelling of 21323340 in words is "twenty-one million, three hundred twenty-three thousand, three hundred forty".