21406602 has 16 divisors (see below), whose sum is σ = 48929472. Its totient is φ = 6116160.

The previous prime is 21406589. The next prime is 21406643. The reversal of 21406602 is 20660412.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

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, 254799 + ... + 254882.

It is an arithmetic number, because the mean of its divisors is an integer number (3058092).

Almost surely, 2^21406602 is an apocalyptic number.

21406602 is an abundant number, since it is smaller than the sum of its proper divisors (27522870).

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

21406602 is a wasteful number, since it uses less digits than its factorization.

21406602 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 509693.

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

The square root of 21406602 is about 4626.7269208372. The cubic root of 21406602 is about 277.6616572897.

The spelling of 21406602 in words is "twenty-one million, four hundred six thousand, six hundred two".