21609854 has 16 divisors (see below), whose sum is σ = 37429728. Its totient is φ = 9165312.

The previous prime is 21609853. The next prime is 21609869. The reversal of 21609854 is 45890612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21609851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6599 + ... + 9314.

It is an arithmetic number, because the mean of its divisors is an integer number (2339358).

Almost surely, 2^21609854 is an apocalyptic number.

21609854 is a deficient number, since it is larger than the sum of its proper divisors (15819874).

21609854 is a wasteful number, since it uses less digits than its factorization.

21609854 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16019.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 21609854 is about 4648.6400161768. The cubic root of 21609854 is about 278.5376737786.

The spelling of 21609854 in words is "twenty-one million, six hundred nine thousand, eight hundred fifty-four".