21652040 has 16 divisors (see below), whose sum is σ = 48717180. Its totient is φ = 8660800.

The previous prime is 21652003. The next prime is 21652061. The reversal of 21652040 is 4025612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21473956 + 178084 = 4634^2 + 422^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 270611 + ... + 270690.

Almost surely, 2^21652040 is an apocalyptic number.

21652040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21652040 is an abundant number, since it is smaller than the sum of its proper divisors (27065140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21652040 is a wasteful number, since it uses less digits than its factorization.

21652040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 541312 (or 541308 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21652040 is about 4653.1752599703. The cubic root of 21652040 is about 278.7188064593.

Adding to 21652040 its reverse (4025612), we get a palindrome (25677652).

The spelling of 21652040 in words is "twenty-one million, six hundred fifty-two thousand, forty".