21340512 has 36 divisors (see below), whose sum is σ = 60687900. Its totient is φ = 7113408.

The previous prime is 21340511. The next prime is 21340523. The reversal of 21340512 is 21504312.

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 congruent number.

It is not an unprimeable number, because it can be changed into a prime (21340511) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36762 + ... + 37337.

It is an arithmetic number, because the mean of its divisors is an integer number (1685775).

Almost surely, 2^21340512 is an apocalyptic number.

It is an amenable number.

21340512 is an abundant number, since it is smaller than the sum of its proper divisors (39347388).

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

21340512 is a wasteful number, since it uses less digits than its factorization.

21340512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74115 (or 74104 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21340512 is about 4619.5792016157. The cubic root of 21340512 is about 277.3756150607.

Adding to 21340512 its reverse (21504312), we get a palindrome (42844824).

The spelling of 21340512 in words is "twenty-one million, three hundred forty thousand, five hundred twelve".