21340864 has 14 divisors (see below), whose sum is σ = 42348404. Its totient is φ = 10670400.

The previous prime is 21340861. The next prime is 21340883. The reversal of 21340864 is 46804312.

It is not an unprimeable number, because it can be changed into a prime (21340861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166662 + ... + 166789.

It is an arithmetic number, because the mean of its divisors is an integer number (3024886).

Almost surely, 2^21340864 is an apocalyptic number.

It is an amenable number.

21340864 is a deficient number, since it is larger than the sum of its proper divisors (21007540).

21340864 is an equidigital number, since it uses as much as digits as its factorization.

21340864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333463 (or 333453 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 21340864 is about 4619.6173001668. The cubic root of 21340864 is about 277.3771401050.

The spelling of 21340864 in words is "twenty-one million, three hundred forty thousand, eight hundred sixty-four".