21536669 has 24 divisors (see below), whose sum is σ = 27681024. Its totient is φ = 16394400.

The previous prime is 21536657. The next prime is 21536687. The reversal of 21536669 is 96663512.

It is not a de Polignac number, because 21536669 - 2¹⁶ = 21471133 is a prime.

It is a super-2 number, since 2×21536669² = 927656223231122, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21536629) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 39539 + ... + 40079.

It is an arithmetic number, because the mean of its divisors is an integer number (1153376).

Almost surely, 2^21536669 is an apocalyptic number.

It is an amenable number.

21536669 is a deficient number, since it is larger than the sum of its proper divisors (6144355).

21536669 is a wasteful number, since it uses less digits than its factorization.

21536669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 617 (or 606 counting only the distinct ones).

The product of its digits is 58320, while the sum is 38.

The square root of 21536669 is about 4640.7616831723. The cubic root of 21536669 is about 278.2228816614. Note that the first 3 decimals are identical.

The spelling of 21536669 in words is "twenty-one million, five hundred thirty-six thousand, six hundred sixty-nine".