21454997 has 2 divisors, whose sum is σ = 21454998. Its totient is φ = 21454996.

The previous prime is 21454973. The next prime is 21455011. The reversal of 21454997 is 79945412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21446161 + 8836 = 4631^2 + 94^2 .

It is a cyclic number.

It is not a de Polignac number, because 21454997 - 2¹² = 21450901 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21454297) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10727498 + 10727499.

It is an arithmetic number, because the mean of its divisors is an integer number (10727499).

Almost surely, 2^21454997 is an apocalyptic number.

It is an amenable number.

21454997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21454997 is an equidigital number, since it uses as much as digits as its factorization.

21454997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 41.

The square root of 21454997 is about 4631.9539073700. The cubic root of 21454997 is about 277.8707411099.

The spelling of 21454997 in words is "twenty-one million, four hundred fifty-four thousand, nine hundred ninety-seven".