21269210 has 16 divisors (see below), whose sum is σ = 40536936. Its totient is φ = 8007168.

The previous prime is 21269197. The next prime is 21269233. The reversal of 21269210 is 1296212.

It can be written as a sum of positive squares in 4 ways, for example, as 13712209 + 7557001 = 3703^2 + 2749^2 .

It is a Curzon 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, 62387 + ... + 62726.

Almost surely, 2^21269210 is an apocalyptic number.

21269210 is a deficient number, since it is larger than the sum of its proper divisors (19267726).

21269210 is a wasteful number, since it uses less digits than its factorization.

21269210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125137.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21269210 is about 4611.8553750091. The cubic root of 21269210 is about 277.0663518842.

The spelling of 21269210 in words is "twenty-one million, two hundred sixty-nine thousand, two hundred ten".