21652481 has 4 divisors (see below), whose sum is σ = 21866964. Its totient is φ = 21438000.

The previous prime is 21652427. The next prime is 21652483. The reversal of 21652481 is 18425612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19280881 + 2371600 = 4391^2 + 1540^2 .

It is a cyclic number.

It is not a de Polignac number, because 21652481 - 2¹⁸ = 21390337 is a prime.

It is a super-2 number, since 2×21652481² = 937659866910722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21652483) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107090 + ... + 107291.

It is an arithmetic number, because the mean of its divisors is an integer number (5466741).

Almost surely, 2^21652481 is an apocalyptic number.

It is an amenable number.

21652481 is a deficient number, since it is larger than the sum of its proper divisors (214483).

21652481 is a wasteful number, since it uses less digits than its factorization.

21652481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214482.

The product of its digits is 3840, while the sum is 29.

The square root of 21652481 is about 4653.2226467256. Note that the first 3 decimals coincide. The cubic root of 21652481 is about 278.7206987238.

The spelling of 21652481 in words is "twenty-one million, six hundred fifty-two thousand, four hundred eighty-one".