21948481 has 8 divisors (see below), whose sum is σ = 22272264. Its totient is φ = 21626880.

The previous prime is 21948469. The next prime is 21948497. The reversal of 21948481 is 18484912.

It can be written as a sum of positive squares in 4 ways, for example, as 6076225 + 15872256 = 2465^2 + 3984^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21948481 is a prime.

It is a super-2 number, since 2×21948481² = 963471636414722, which contains 22 as substring.

It is a deceptive number, since it divides R_21948480.

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 21948481.

It is not an unprimeable number, because it can be changed into a prime (21948461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33921 + ... + 34561.

It is an arithmetic number, because the mean of its divisors is an integer number (2784033).

Almost surely, 2^21948481 is an apocalyptic number.

It is an amenable number.

21948481 is a deficient number, since it is larger than the sum of its proper divisors (323783).

21948481 is an equidigital number, since it uses as much as digits as its factorization.

21948481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1091.

The product of its digits is 18432, while the sum is 37.

The square root of 21948481 is about 4684.9205969792. The cubic root of 21948481 is about 279.9850374658.

The spelling of 21948481 in words is "twenty-one million, nine hundred forty-eight thousand, four hundred eighty-one".