21976481 has 2 divisors, whose sum is σ = 21976482. Its totient is φ = 21976480.

The previous prime is 21976463. The next prime is 21976499. The reversal of 21976481 is 18467912.

It is a balanced prime because it is at equal distance from previous prime (21976463) and next prime (21976499).

It can be written as a sum of positive squares in only one way, i.e., 19140625 + 2835856 = 4375^2 + 1684^2 .

It is a cyclic number.

It is not a de Polignac number, because 21976481 - 2¹⁸ = 21714337 is a prime.

It is a super-2 number, since 2×21976481² = 965931434286722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21976421) 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 as a sum of consecutive naturals, namely, 10988240 + 10988241.

It is an arithmetic number, because the mean of its divisors is an integer number (10988241).

Almost surely, 2^21976481 is an apocalyptic number.

It is an amenable number.

21976481 is a deficient number, since it is larger than the sum of its proper divisors (1).

21976481 is an equidigital number, since it uses as much as digits as its factorization.

21976481 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 38.

The square root of 21976481 is about 4687.9079555810. The cubic root of 21976481 is about 280.1040472159.

The spelling of 21976481 in words is "twenty-one million, nine hundred seventy-six thousand, four hundred eighty-one".