21010427 has 2 divisors, whose sum is σ = 21010428. Its totient is φ = 21010426.

The previous prime is 21010411. The next prime is 21010433. The reversal of 21010427 is 72401012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21010427 - 2⁴ = 21010411 is a prime.

It is not a weakly prime, because it can be changed into another prime (21010127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505213 + 10505214.

It is an arithmetic number, because the mean of its divisors is an integer number (10505214).

Almost surely, 2^21010427 is an apocalyptic number.

21010427 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010427 is an equidigital number, since it uses as much as digits as its factorization.

21010427 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 21010427 is about 4583.7132327405. The cubic root of 21010427 is about 275.9380724675.

Adding to 21010427 its reverse (72401012), we get a palindrome (93411439).

The spelling of 21010427 in words is "twenty-one million, ten thousand, four hundred twenty-seven".