21260406 has 16 divisors (see below), whose sum is σ = 42634800. Its totient is φ = 7067808.

The previous prime is 21260377. The next prime is 21260413. The reversal of 21260406 is 60406212.

It is a happy number.

It is a congruent 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, 2221 + ... + 6888.

It is an arithmetic number, because the mean of its divisors is an integer number (2664675).

Almost surely, 2^21260406 is an apocalyptic number.

21260406 is an abundant number, since it is smaller than the sum of its proper divisors (21374394).

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

21260406 is a wasteful number, since it uses less digits than its factorization.

21260406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9503.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 21260406 is about 4610.9007796742. The cubic root of 21260406 is about 277.0281177607.

Adding to 21260406 its reverse (60406212), we get a palindrome (81666618).

The spelling of 21260406 in words is "twenty-one million, two hundred sixty thousand, four hundred six".