21534617 has 12 divisors (see below), whose sum is σ = 24091620. Its totient is φ = 19112352.

The previous prime is 21534577. The next prime is 21534659. The reversal of 21534617 is 71643512.

It can be written as a sum of positive squares in 2 ways, for example, as 6911641 + 14622976 = 2629^2 + 3824^2 .

It is not a de Polignac number, because 21534617 - 2¹⁸ = 21272473 is a prime.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21534617.

It is not an unprimeable number, because it can be changed into a prime (21534517) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 89984 + ... + 90222.

It is an arithmetic number, because the mean of its divisors is an integer number (2007635).

Almost surely, 2^21534617 is an apocalyptic number.

It is an amenable number.

21534617 is a deficient number, since it is larger than the sum of its proper divisors (2557003).

21534617 is an equidigital number, since it uses as much as digits as its factorization.

21534617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520 (or 281 counting only the distinct ones).

The product of its digits is 5040, while the sum is 29.

The square root of 21534617 is about 4640.5405935085. The cubic root of 21534617 is about 278.2140450815.

The spelling of 21534617 in words is "twenty-one million, five hundred thirty-four thousand, six hundred seventeen".