21397043 has 2 divisors, whose sum is σ = 21397044. Its totient is φ = 21397042.

The previous prime is 21397009. The next prime is 21397069. The reversal of 21397043 is 34079312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21397043 - 2¹⁰ = 21396019 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21396997 and 21397015.

It is not a weakly prime, because it can be changed into another prime (21397093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10698521 + 10698522.

It is an arithmetic number, because the mean of its divisors is an integer number (10698522).

Almost surely, 2^21397043 is an apocalyptic number.

21397043 is a deficient number, since it is larger than the sum of its proper divisors (1).

21397043 is an equidigital number, since it uses as much as digits as its factorization.

21397043 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 29.

The square root of 21397043 is about 4625.6937858012. The cubic root of 21397043 is about 277.6203217094.

The spelling of 21397043 in words is "twenty-one million, three hundred ninety-seven thousand, forty-three".