21340506 has 16 divisors (see below), whose sum is σ = 46561248. Its totient is φ = 6466800.

The previous prime is 21340489. The next prime is 21340511. The reversal of 21340506 is 60504312.

It is a happy number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 161605 + ... + 161736.

It is an arithmetic number, because the mean of its divisors is an integer number (2910078).

Almost surely, 2^21340506 is an apocalyptic number.

21340506 is an abundant number, since it is smaller than the sum of its proper divisors (25220742).

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

21340506 is a wasteful number, since it uses less digits than its factorization.

21340506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323357.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 21340506 is about 4619.5785522058. The cubic root of 21340506 is about 277.3755890655.

Adding to 21340506 its reverse (60504312), we get a palindrome (81844818).

The spelling of 21340506 in words is "twenty-one million, three hundred forty thousand, five hundred six".