21535616 has 16 divisors (see below), whose sum is σ = 42903240. Its totient is φ = 10767744.

The previous prime is 21535601. The next prime is 21535621. The reversal of 21535616 is 61653512.

It is a tau number, because it is divible by the number of its divisors (16).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83996 + ... + 84251.

Almost surely, 2^21535616 is an apocalyptic number.

It is an amenable number.

21535616 is a deficient number, since it is larger than the sum of its proper divisors (21367624).

21535616 is an equidigital number, since it uses as much as digits as its factorization.

21535616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168261 (or 168249 counting only the distinct ones).

The product of its digits is 5400, while the sum is 29.

The square root of 21535616 is about 4640.6482305816. The cubic root of 21535616 is about 278.2183471708.

The spelling of 21535616 in words is "twenty-one million, five hundred thirty-five thousand, six hundred sixteen".