21496905 has 24 divisors (see below), whose sum is σ = 37370112. Its totient is φ = 11431584.

The previous prime is 21496903. The next prime is 21496913. The reversal of 21496905 is 50969412.

It is not a de Polignac number, because 21496905 - 2¹ = 21496903 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 21496905.

It is not an unprimeable number, because it can be changed into a prime (21496901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26922 + ... + 27708.

It is an arithmetic number, because the mean of its divisors is an integer number (1557088).

Almost surely, 2^21496905 is an apocalyptic number.

It is an amenable number.

21496905 is a deficient number, since it is larger than the sum of its proper divisors (15873207).

21496905 is a wasteful number, since it uses less digits than its factorization.

21496905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1405 (or 1402 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 21496905 is about 4636.4754933031. The cubic root of 21496905 is about 278.0515448822.

The spelling of 21496905 in words is "twenty-one million, four hundred ninety-six thousand, nine hundred five".