21478351 has 2 divisors, whose sum is σ = 21478352. Its totient is φ = 21478350.

The previous prime is 21478339. The next prime is 21478363. The reversal of 21478351 is 15387412.

It is a balanced prime because it is at equal distance from previous prime (21478339) and next prime (21478363).

It is a cyclic number.

It is not a de Polignac number, because 21478351 - 2¹¹ = 21476303 is a prime.

It is a super-2 number, since 2×21478351² = 922639123358402, which contains 22 as substring.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21478651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10739175 + 10739176.

It is an arithmetic number, because the mean of its divisors is an integer number (10739176).

Almost surely, 2^21478351 is an apocalyptic number.

21478351 is a deficient number, since it is larger than the sum of its proper divisors (1).

21478351 is an equidigital number, since it uses as much as digits as its factorization.

21478351 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6720, while the sum is 31.

The square root of 21478351 is about 4634.4741880822. The cubic root of 21478351 is about 277.9715263352.

The spelling of 21478351 in words is "twenty-one million, four hundred seventy-eight thousand, three hundred fifty-one".