21996481 has 8 divisors (see below), whose sum is σ = 23725800. Its totient is φ = 20272512.

The previous prime is 21996473. The next prime is 21996493. The reversal of 21996481 is 18469912.

It can be written as a sum of positive squares in 4 ways, for example, as 5022081 + 16974400 = 2241^2 + 4120^2 .

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

It is not a de Polignac number, because 21996481 - 2³ = 21996473 is a prime.

It is a super-2 number, since 2×21996481² = 967690352766722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21996451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12831 + ... + 14443.

It is an arithmetic number, because the mean of its divisors is an integer number (2965725).

Almost surely, 2^21996481 is an apocalyptic number.

It is an amenable number.

21996481 is a deficient number, since it is larger than the sum of its proper divisors (1729319).

21996481 is a wasteful number, since it uses less digits than its factorization.

21996481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2675.

The product of its digits is 31104, while the sum is 40.

The square root of 21996481 is about 4690.0406181610. The cubic root of 21996481 is about 280.1889923046.

The spelling of 21996481 in words is "twenty-one million, nine hundred ninety-six thousand, four hundred eighty-one".