21454397 has 2 divisors, whose sum is σ = 21454398. Its totient is φ = 21454396.

The previous prime is 21454393. The next prime is 21454409. The reversal of 21454397 is 79345412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15007876 + 6446521 = 3874^2 + 2539^2 .

It is a cyclic number.

It is not a de Polignac number, because 21454397 - 2² = 21454393 is a prime.

It is a Chen prime.

It is a zygodrome in base 3.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21454393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10727198 + 10727199.

It is an arithmetic number, because the mean of its divisors is an integer number (10727199).

Almost surely, 2^21454397 is an apocalyptic number.

It is an amenable number.

21454397 is a deficient number, since it is larger than the sum of its proper divisors (1).

21454397 is an equidigital number, since it uses as much as digits as its factorization.

21454397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30240, while the sum is 35.

The square root of 21454397 is about 4631.8891394333. The cubic root of 21454397 is about 277.8681508198.

The spelling of 21454397 in words is "twenty-one million, four hundred fifty-four thousand, three hundred ninety-seven".