21475451 has 2 divisors, whose sum is σ = 21475452. Its totient is φ = 21475450.

The previous prime is 21475417. The next prime is 21475459. The reversal of 21475451 is 15457412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21475451 - 2⁶ = 21475387 is a prime.

It is a super-2 number, since 2×21475451² = 922389991306802, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21475459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10737725 + 10737726.

It is an arithmetic number, because the mean of its divisors is an integer number (10737726).

Almost surely, 2^21475451 is an apocalyptic number.

21475451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21475451 is an equidigital number, since it uses as much as digits as its factorization.

21475451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5600, while the sum is 29.

The square root of 21475451 is about 4634.1613049181. The cubic root of 21475451 is about 277.9590152302.

The spelling of 21475451 in words is "twenty-one million, four hundred seventy-five thousand, four hundred fifty-one".