21974543 has 2 divisors, whose sum is σ = 21974544. Its totient is φ = 21974542.

The previous prime is 21974503. The next prime is 21974551. The reversal of 21974543 is 34547912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21974543 - 2⁶ = 21974479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21974503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10987271 + 10987272.

It is an arithmetic number, because the mean of its divisors is an integer number (10987272).

Almost surely, 2^21974543 is an apocalyptic number.

21974543 is a deficient number, since it is larger than the sum of its proper divisors (1).

21974543 is an equidigital number, since it uses as much as digits as its factorization.

21974543 is an evil number, because the sum of its binary digits is even.

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

The square root of 21974543 is about 4687.7012490132. The cubic root of 21974543 is about 280.0958132983.

The spelling of 21974543 in words is "twenty-one million, nine hundred seventy-four thousand, five hundred forty-three".