21970447 has 2 divisors, whose sum is σ = 21970448. Its totient is φ = 21970446.

The previous prime is 21970433. The next prime is 21970469. The reversal of 21970447 is 74407912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21970447 - 2¹⁵ = 21937679 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21970427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10985223 + 10985224.

It is an arithmetic number, because the mean of its divisors is an integer number (10985224).

Almost surely, 2^21970447 is an apocalyptic number.

21970447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21970447 is an equidigital number, since it uses as much as digits as its factorization.

21970447 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14112, while the sum is 34.

The square root of 21970447 is about 4687.2643407429. The cubic root of 21970447 is about 280.0784091633.

The spelling of 21970447 in words is "twenty-one million, nine hundred seventy thousand, four hundred forty-seven".