21401047 has 2 divisors, whose sum is σ = 21401048. Its totient is φ = 21401046.

The previous prime is 21400997. The next prime is 21401053. The reversal of 21401047 is 74010412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21401047 - 2⁷ = 21400919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21401447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10700523 + 10700524.

It is an arithmetic number, because the mean of its divisors is an integer number (10700524).

Almost surely, 2^21401047 is an apocalyptic number.

21401047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21401047 is an equidigital number, since it uses as much as digits as its factorization.

21401047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 224, while the sum is 19.

The square root of 21401047 is about 4626.1265654973. The cubic root of 21401047 is about 277.6376375356.

Adding to 21401047 its reverse (74010412), we get a palindrome (95411459).

The spelling of 21401047 in words is "twenty-one million, four hundred one thousand, forty-seven".